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TESIS DEFENDIDA POR Alfonso Medellin Ortiz
Y APROBADA POR-EL SIGUIENTE COMITE
Dr. Oscar Sos2/Nishizaki Director del Comité
ibérto Gaxiola Castro Dr. Horacio Jésus de la Cueva
Miembro del Comité Salcedo
Miembro del Comité
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Dr. Raul Ravel
Miembro del comité Miembro del Comité
ojo Dra. Suzanne Kohin
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Nad [ewar ¢
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Dra. Heidi Dewar
“ Miembro del Comité
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Dr. Luis
Coordinador del programa de posgrado en Ecologia Marina
Dr. David Milario Covarrubias Rosales
Encargado del Despacho dela Direccién de Estudios de
Posgrado
alderén Aguilera
CENTRODE INVESTIGACION CIENTIFICA Y EDUCACION SUPERIOR DE
ENSENADA
CICESE
PROGRAMA DE POSGRADO ENECOLOGiIA MARINA
MOVEMENTS OF THE MAKO SHARKIN THE NORTHEASTERNPACIFIC.
TESIS
que para cubrir parcialmente los requisitos necesarios para obtenerel grado de MAESTRO EN CIENCIAS
Presenta:
ALFONSO MEDELLIN ORTIZ
Resumende la tesis de Alfonso Medellin Ortiz, presentada como requisito parcial para la obtencién del grado de Maestro en Ciencias en Ecologia Marina. Ensenada, BC. Marzo
2008.
MOVIMIENTOSDEL TIBURON MAKO EN EL PACIFICO NORESTE
Resumen aprobadopor:
Dr. Oscar Sosa Nishizaki
Director.
Se marcaron veintitrés tiburones mako (/surus oxyrinchus Rafinesque 1810)
durante el seguimiento anual de juveniles de tiburones pelagicos del National Oceanic &
Atmospheric Administration (NOAA) Southwest Fisheries Science Center, a bordo de la
E/I David Starr Jordan de 2004 a 2005, y un tiburén durante un viaje de marcaje realizado a bordo de la E/P YUMANOenEnero 2006 utilizando marcas tipo PAT y SPOT.Latalla de los tiburones vario de 114 a 281 cm Longitud Total; la razén de sexos macho — hembra fue de 5:1. Veinte de los 24 tiburones marcados fueron juveniles. Analizamos la informacion de 13 marcas PAT y 21 SPOT. La duraciénde los seguimientos vario de 36 a 470 dias, mientras que la cercania a la costa fue de 0.5 a = 2,300 millas nauticas. El tiempo a profundidad y temperatura para los 13 tiburones con marca PAT mostré que lostiburones experimentaron profundidades de 0 a 500 m, permaneciendo el 60% del tiempo
entre aguas superficiales y 150 m de profundidad. Estos tiburones permanecieron la mayor
parte del tiempo en aguas con temperaturas entre los 12 y 22° C, a pesar de que experimentaron temperaturas tan bajas como 4° C. Se encontraron diferencias altamente significativas en el tiempo a profundidad y temperatura entre dia y noche, con base enarchivos completos de dos tiburones Oe 0.05, 14 = 1.838, p< 0.0001; y ¢ 0.05, 122 = 1.051, p<
0.0001, respectivamente). Las localizaciones de los 21 tiburones mostraron un amplio movimiento. Mientras que algunos tiburones se mantuvieron dentro de la Cuenca de California a lo largo del afio, se observé un patron de movimiento hacia el norte durante los meses de junio a octubre, y hacia el sur en los meses de noviembre a mayo, aparentemente siguiendo los movimientos norte — sur que presenta la Corriente de California. Los tiburones se desplazaron a lo largo de la costa pero también se desplazaron tan lejos de la costa cerca de 370 millas nauticas hacia Hawai. Debido a que veinte de los tiburones marcados fueron juveniles, se piensa que este comportamiento costero esta relacionado con movimientos entre zonas de crianza en la Cuenca de California y a lo
largo de la Peninsula de Baja California.
ii
A thesis submitted in partial satisfaction for the requirements of Master of Science in Marine Ecology by Alfonso Medellin Ortiz.
MOVEMENTS OF THE MAKO SHARK IN THE NORTHEASTERN PACIFIC
Abstract approved by:
’ Dr. Oscar Sosa Nishizaki
Director.
Twenty three juvenile mako sharks (/surus oxyrinchus Rafinesque 1810) were tagged during the National Oceanic & Atmospheric Administration (NOAA) Southwest Fisheries Science Center’s annual juvenile pelagic shark survey on board the NOAA ship R/V David Starr Jordan from 2004 to 2006, and one shark was tagged during trip in the winter of 2006 on board the Mexican commercial fishing vessel YUMANO using PAT and SPOTtype tags. Shark size ranged from 114 to 281 cm in Total Length; the male-female
sex ratio was 5:1. Twenty of 24 tagged sharks were juveniles. We analyzed data from 13
PATand 21 SPOTtags. Tracking days ranged from 36 to 470, while distances from shore varied from 0.5 nm to ~ 2,300 nm. Time at depth data for all 13 sharks showed that the juvenile mako sharks experienced depths from surface to 500 m, but spent most of the time(>60%) between surface and 150 m. Sharks spent most of time in water temperatures
between 12 and 22° C, even though they experienced temperatures as low as 4° C. Basedonarchival data of two sharks, differences in depth and temperature between day and night
were statistically significant 62 0.05, 14 = 1.838, p< 0.0001; and ¢ 0.05, 12 = 1.051, p< 0.0001, respectively). The near real time locations of all 21 sharks showed a wide range of movement. While some sharks tended to stay in the Southern California Bight (SCB) through out the year; we observed a year-around trend of near shore northward movement during June—October and southward from November to May following the California Current’s southward and northward expansion and retraction trends. Sharks moved along the coastline but also traveled as far as 370 nm off Hawaii. As 20 tagged sharks werejuveniles, we think this coastal behavior may be related to the movements between nursery
groundsin the SCBandalong the westcoast of Baja California peninsula.iii
“A la curiosidad, porque mate al gato”
iv
ACKNOWLEDGMENTS
Dr. Oscar Sosa Nishizaki for all the support, invaluable knowledge, all the
opportunities and confidence deposited in me along the years
Drs. Suzanne Kohin and Heidi Dewarfor sharing their knowledge, experience, and
giving methe opportunity to learn from them
Drs. Gilberto Gaxiola, Horacio de la Cueva and Raul Rangel Rojo for their support,
orientation and valuable comments along this process
CONACYTfor the scholarship granted
Carmen, Micks, Erick and Omar for their help, friendship, hours of hard work,
meals,laughter, analysis, laughter, planning, laughter
My parents Columba and Alfonso and grand parents Blanca and Daniel for
everything
The crew of the Mexican F/V Yumanoforletting us work side by side with them
Dr. Barbara Block and the Project TOPP for the opportunity to work with the mako
sharks; all tags and access to data bases
Nadia for all the support, ideas, caring and for making me a better person
Resumen Ejecutivo de la tesis de Alfonso Medellin Ortiz, presentada como requisito parcial para la obtencién del grado de Maestro en Ciencias en Ecologia Marina. Ensenada, BC. Mexico. Marzo de 2008.
MOVIMIENTOSDEL TIBURON MAKO EN EL PACIFICO NORESTE
MOVEMENTS OF MAKO SHARK(Lsurus oxyrinchus) IN THE NORTHEASTERN PACIFIC Resumen aprobadopor:
Dr. Oscar Sosa Nishizaki Director
I, INTRODUCCION
Se conoce poco acerca del uso del habitat por parte de la mayoria de grandes predadores pelagicos marinos. Los animales pelagicos han representado un gran reto para los investigadores debido a su tamafio, velocidad y distribucion a lo largo del vasto habitat oceanico, y a la dificultad que representa seguirlos sin la instrumentacion adecuada (Block, et al, 2005). Un grupo de grandes predadores pelagicos que ha sido particularmente dificil de estudiar es el de los tiburones pelagicos. Como con cualquier otro organismo, los tiburones no se encontraran en todos los habitats de su distribucion, sino que tendran habitats particulares en los que pasaran la mayor parte del tiempo (Simpfendorfer y Heupel, 2004).
Los esfuerzos porincluir informacion mas compleja acerca del habitat en el manejo de pesquerias han ido aumentando conforme ha aumentado la disponibilidad de nuevas herramientas para estudiar grandes animales peldgicos. Estas herramientas incluyen la telemetria actstica y satelital, ademas de las marcas archivadoras que han permitido el avance de nuestra habilidad para estudiar ecosistemas en el océano abierto (Block, 2005). El desarrollo del marcaje electrénico y tecnologia de sensores remotos dio pie a una nueva era para los bidlogos marinos. Las marcas modernas estan compuestas de poderosos microprocesadores (no solo memoria) y sensores mejorados que proveen de muestreo de los movimientos y comportamientos del animal mas rapidos y precisos, asi como del ambiente. Ademas, los sensores remotos proveen de imagenes globales de alta resolucién que permiten una mejor integracién de la informacién ambiental y la informacion colectada por los animales marcados. Estas nuevas herramientas estan generando avances en la biologia y mejorando nuestra capacidad de contestar preguntas ecoldgicas (Block,
2005).
vi
de telemetria actstica. En el océano Pacifico, Holts y Bedford (1993) siguieron a 3 juveniles de tiburén mako dentro de la Cuenca de California, y no encontraron un patron circadiano tanto el los movimientos verticales como en los horizontales, y tampoco encontraron asociacién con islas, bancos u otras caracteristicas del fondo. Los autores sugieren que los makos dentro de la cuenca de California tienen una amplia distribucién de habitats, como los makos en el océano Atlantico, y que para identificas cualquier patrén u orientacién de los movimientos seria necesario expandirel tiempo de seguimiento de los tiburones.
En un segundo estudio, Sepulveda ef al. (2004) utilizaron telemetria actstica para seguir los movimientos de 7 juveniles de tiburén mako marcados dentro de la Cuenca de California, por un periodo de 7 a 45 horas. Los autores observaron que los tiburones marcados permanecieron un 80% del tiempo en aguasentre los 0 y 12 m de profundidad, y quelas incursiones en aguas masfrias y profundas fueron mas frecuentes duranteel dia.
1.1. HIPOTESIS
Debido las caracteristicas biolégicas del tiburon mako, la hipdtesis de trabajo es que los movimientos de los tiburones mako marcados estan correlacionados con las condiciones ambientales tales como profundidad y temperatura.
1.2. OBJETIVOS
vii
Il. MATERIALES Y METODOS
Para este estudio se marcaron un total de 24 tiburones mako. Veintitrés de estos fueron marcados durante el crucero anual de revision de tiburones juveniles pelagicos del National Oceanic & Atmospheric Administration (NOAA) Southwest Fisheries Science Center’s (SWFSC) abordo de la NOAA R/V David Starr Jordan entre Junio 2004 y Julio 2005. Se desplegaron un total de 17 PATs y 22 SPOTs. Quince tiburones fueron marcados con ambostipos de marca (PAT/SPOT),siete tiburones se marcaron unicamente utilizando SPOTs,y 2 tiburones se marcaron tnicamente utilizando una PAT.
Ocho marcas PAT fueron programadas para muestrear profundidad, temperatura y nivel de luz cada minuto y guardar la informacién para ser transmitida via satélite en resumenes de 12 horas. Las 9 restantes fueron programadas para muestrear estos parametros cada 30 segundos y enviar restimenes de 12 horas. Las marcas PAT se programaron para quese liberaran del anclaje ya sea 180 0 210 dias después de la fecha de despliegue. Las marcas SPOT fueron programadas para trasmitir su localizacién cada vez que la marca estuviera seca (cada vez queel tiburén rompiera el espejo de agua) hasta 500 trasmisionespordia.
Se analizaron los archivos completos asi como todos los mensajes satelitales
recibidos por Argos en la forma de “ds” o “prv”. Se extrajeron histogramas de 12 horas del
tiempo a profundidad y temperatura asi comoelperfil de profundidad y temperatura (PDT) de cada marcatipo PAT utilizando el programa WC-AMP.Los archivos completos fueron extraidos manualmente utilizando el programa Instrument Helper para lograr separar lainformacion de dia y noche tomando en cuenta las variaciones estacionales en la duracién
del dia. Toda la informacién de las marcas PAT fue separada entres intervalos de talla:
<150, 160 — 180 y >180 cm de LT para examinar comportamientos relacionados con la talla. Ademas, toda la informacién relativa a profundidad, temperatura y localizacién se separd en 4 areas para examinar comportamiento relacionado al area; estas areas son: Provincia de Oregon; Provincia de San Diego; Provincia Cortéz y Provincia Mexicana. La seleccién de estas areas se debid a sus caracteristicas oceanograficas y biogeograficas especiales (Huyer, 1983; Durazo y Baumgartner, 2002; Horn ef al., 2006). El uso dehabitat vertical fue calculado utilizando la informacion de las marcas PAT. Nose calculo
el tiempo a profundidad y temperatura durante el dia y noche debido a la programacion de
las marcas. Los histogramas de tiempo a profundidad y temperatura de ambos archivos
completos se calcularon teniendo en cuenta las variaciones estacionales en la longitud deldia.
Todos los datos de profundidad y temperatura fueron separados de acuerdo a su distancia a la costa con el motivo de examinar posibles diferencias entre comportamientos costeros y oceanicos. Se consideré una distancia de 30 millas nduticas (55.5 Km.) como la frontera entre ambientes oceanico y costero debido a que la plataforma continental a lo
largo del Pacifico Noreste es generalmente angosta e inclinada con un ancho promedio de
11 millas nauticas (20 Km.). Solo se realizo este andlisis para aquellos tiburones que
fueron marcados utilizando marcas SPOT debidoa la alta precisién en la localizacion.
viii
la existencia de preferencias de profundidad y temperatura durante el dia y la noche utilizando una prueba de bondadde ajuste (x? de unavia).
Se combinaron las localizaciones por fecha de todos los tiburones para examinar la presencia de estacionalidad en los movimientos horizontales. Se calculéd la densidad en Kernel utilizando el promedio de la posicién diaria por cada tiburén por medio de la herramienta incluida en el programa ArcGis Software 9.2. La densidad en Kernel fue utilizada solo como herramienta para identificar dreas de agregacién y fue comparada graficamente con imagenes de produccién primaria obtenidas partir del procesamiento de imagenes de temperatura superficial del mar, concentracién de clorofila a y radiacién fotosintéticamente activa con el programa Windows Image Manager 6.45 (Kahru, 2006), donde la produccion primaria se calculo utilizando la profundidad de la zona eufética de Morel — Bretén y el modelo de PBopt de Behrenfeld — Fallkowski (1997).
Ii. RESULTADOS
III.1. COMPORTAMIENTO GENERAL DEL TIBURON MAKO
Los veinticuatro tiburones marcados variaron entalla desde los 114 hasta los 281 cm LT; la razon de sexos hembra — macho fue de 5:1. Con base enlo reportado por Joung y Hsu (2005) 20 de los tiburones marcados se consideraron como juveniles. La hembra marcada mas grande fue de 177 cm LT. Se analizaron los datos de 13 marcas PAT y 21 marcas SPOT. Nose recupero informacion de 5 marcas. Los dias de seguimiento variaron de 36 a 470;las distancias recorridas de los puntos de despliegue a los puntosde liberacién variaron de 1,108 a 25,491 Km. La velocidad promedio de todoslos tiburones fue de 0.686 + 0.024 ms”. El desplazamiento al norte més lejano observado fue en dreas al norte de Oregon, mientras que el desplazamiento al sur mas lejano fue en la Corriente NorEcuatorial, alrededor de los 13° 45.150! latitud Norte y 120° 12.480! longitud Oeste.
El tiempo a profundidad para los 13 tiburones que llevaban marcas PAT mostré tiburones mako juveniles y adultos experimentaron profundidades desde la superficie hasta los 356 m, pero permanecieron el 95% del tiempo entre la superficie y 150 m de profundidad. Ademas, los tiburones permanecieron 95% del tiempo en aguas con temperaturasentre los 12 y 22 ° C, a pesar de que experimentaron temperaturas de 7° C;la
temperatura superficial del mar vario de 10 a 27.5° C.
ix
I11.2. COMPORTAMIENTO RELACIONADO CON LA TALLA
Seis de los tiburones marcadospresentaron tallas menores a los 150 em LT (Makos 2, 9, 12, 16, 20 y 23) y en todosellos se observla tendencia a permanecer dentro de la Cuenca de California y la costa de Baja California. Los tiburones se concentraron principalmente desde Punta Concepcién, CA., hasta al sur de Bahia Vizcaino. Sdlo se obtuvo informacién de profundidad y temperatura para dos estaciones, verano y otofio de 2004 y 2005. Durante el seguimiento de estos seis tiburones permanecieron un 55% del
tiempo entre 0 y 5 m de profundidad, mientras que se mantuvieron un 30% entre 5 y 50 m.
E] intervalo de temperatura al cual estuvieron expuestos estos organismos fue de 7 a 26° C, a pesar de que estos 6 tiburones pasaron el 81% del tiempo de seguimiento entre 14 y 22° C. Los perfiles de profundidad y temperatura para 5 de estos 6 tiburones mostraron un amplio intervalo de profundidades y temperaturas durante el verano y otofio de 2004 y2005.
Once de los tiburones marcados fueron de tallas entre 160 y 180 cm LT (Makos7, 8, 10, 11, 13, 14, 15, 18, 22 y 24). Estos tiburones permanecieron mayormente desde Punta Concepcion, CA., y San Quintin, BC., desplazandosetan lejos de la costa hasta 4,600 Km., y tan al norte y sur como Oregon e Isla Revillagigedo, respectivamente. La informacién colectada por estos tiburones comprendié del verano 2005 a la primavera de 2006. En el transcurso de este tiempo, los tiburones permanecieron un 85% del tiempo entre la superficie y 50 m de profundidad, realizando inmersiones a profundidades mayores de 300 m menos de 1% del tiempo de seguimiento. El intervalo de temperatura vario de 7 a mas de 24° C, pero este grupo de tiburones permanecié el 95% del tiempo en aguas con temperaturas entre los 12 y 20° C. Los perfiles de profundidad y temperatura mostraron
cambios estacionales de temperatura a lo largo del area por donde los tiburones se
distribuyeron.
Solamente cuatro tiburones fueron de tallas mayores a los 180 cm LT (Makos1, 3, 5 y 6). Estos tiburones mostraron la misma tendencia de agregacién entre Punta
Concepcion y San Quintin, a pesar de que sudistribucién es un poco masnortefia que la de
los otros grupos. En general, estos tiburones se desplazaron mas lejos de la costa (hasta 5,000 Km.) y se mantuvieron en areas fuera de la costa por mas tiempo. Solo se recupero informacién de tiempo a profundidad y temperatura de los Makos 1 y 3; estos machos adultos fueron seguidos por un total acumulativo de 407 dias, de verano 2004 a Enero 2005. Durante este tiempo ambostiburones permanecieron 90% entre la superficie y 50 mde profundidad, realizando incursiones a mas de 100 m de profundidad menosdel 10% del
tiempo. Asi mismo, ambos tiburones permanecieron 80% del tiempo en aguas con temperaturas entre los 14 y >24° C. Los perfiles de profundidad y temperatura de estos tiburones reflejaron la amplia gama de profundidades y temperaturas que experimentaron durante el seguimiento.No se encontraron diferencias significativas en el tiempo a profundidad y
III.3. COMPORTAMIENTO RELACIONADO CON EL AREA
Al analizar la informacién de acuerdo las areas propuestas por Hornet al. (2006), se observo una alta densidad de tiburones al norte de Punta Concepcion, CA., dentro de la Provincia de Oregon. Los tiburones tendieron a permanecer dentro de 370 Km. de distancia a la costa, concentrandose mayormente dentro de 185 Km.de distancia a la costa. De acuerdo la informacion recopiladaporlos tiburones durante su estancia en esa area, la temperatura varid de 7 a 16° C, mientras que los movimientos en la columna de agua no sobrepasaron los 270 m de profundidad.
La densidad de tiburones también fue alta dentro de la Provincia de San Diego. La mayor congregacion de tiburones se observé dentro de los primeros 185 Km.de la costa, aunque también se desplazaron hasta 1,000 Km. al oeste de la linea de costa. La temperatura superficial del mar varid de 10.3 a 24° C; las inmersiones dentro de esta area fueron mas profundas de 300 m. ademas, se observé que la temperatura superficial del mar y la temperatura en la columna de agua presentaron variaciones estacionales.
Dentro de la Provincia Cortéz se observé una alta concentracién de tiburones dentro de los primeros 185 Km.de distancia a la costa, al sur de Bahia Magdalena cerca de Los Cabos. En esta Area el comportamiento de los tiburones vario conforme a las caracteristicas oceanograficas. La temperatura varié de 12 a mas de 25° C. Las inmersiones dentro de la columna de agua fueron mas someras cuando la temperatura superficial era menora 18° C, observandose un incremento en la profundidad de las inmersioneshasta los 250 m al incrementar la temperatura superficial. Solo un tiburén se desplaz6 dentro del Golfo de California, desafortunadamente la marca PATseliberé cerca de Los Cabos.
En la Provincia Mexicanase observaron altas densidades de tiburones dentro de los primeros 185 Km.de distancia a la costa, aunque también se observaron densidades altas cerca de islas oceanicas tales como Revillagigedo. En esta area los tiburones experimentaron las temperaturas mas elevadas de todas las areas y su comportamiento se vio modificado por caracteristicas tales como la temperatura superficial del mar, encontrando inmersiones més someras con temperaturas superficiales alrededor de los 20° C, e inmersiones mas profundas cuandola temperatura superficial fue alrededor de 25° C.
Al comparar los sitios de altas densidades de tiburén mako con imagenes de
productividad primaria en la Corriente de California, se observé una relacién aparente
xi
V. CONCLUSIONES
Se observaron diferencias significativas en las preferencias de profundidad y temperatura entre el dia y noche por parte de los tiburones mako, con base en los archivos completos. El comportamiento oscilatorio de inmersiones en la columna de agua fue mas profundo durante el dia. Se piensa que este comportamiento puede estar relacionado con eventos de alimentacién, para evitar ser visto por su presa cuando se aproximapor debajo o para termoregular la temperatura corporal después de haber ingerido a su presa.
También encontramosdiferencias significativas en las preferencias de temperatura y profundidad de manera estacional y dependiendo de su cercania a la costa. Esto puede deberse a cambios estacionales y geograficos en el ambiente a lo largo de California y Baja California.
Para poder observar adecuadamente las diferencias en profundidad y temperatura entre dia y noche de la informacién proveniente de registros resumidos sugerimos programar las marcas PAT para resumirla informacion en periodos de tiempo menores a 12 horas para evitar el traslape de horas entre dia y noche que puede enmascarar las diferencias.
xii
CONTENTS
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Executive Summary...ccccccecec eee ee eeeeee senses ease ease eeeetaeeeeneeeeenenensVv T. INTRODUCTION. 0.0.0... 0c. cccecee eee e cece ee erent nese eeeeeea eee eateetateaeneeatenene mal, 1:1. HYPOTHESIS§.. cgeesoens si wleieaN igaRET ERE TREN seRatES re)
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TI. MATERIALS AND METHODG...0:0ceeceneeeees 6
II.1. TAGGING PROCEDURE AND PROGRAMMING...ceceecseeeeseseeeseeseaesessaeees 6 TI.2. DATA ACQUISITION AND PROCESSING...0:ccecececesessreseeeetueneeeeensenenens 11 TL.2.1. PAT DATA... cc cccccccecceeeee cence seen ence ee eeesssaeeetnteeseenenennens 11 II.2.2. LIGHT LEVEL BASED GEO-LOCATION FROM PATTAGS... we 12 TI.2.3, VERTICAL MOVEMENTANALYSIS...0c0cesesssceeseseetneeeeeeeeeseuenes 12 IL.3, HORIZONTAL MOVEMENT. ANALYSISiis. cisssaevaeses ceseeceses ons ven aaevareverescorens 15
1.3.1. SPOT DATAss weave cxvsaans canine 15
THD. RESULTS... 0. cece ec ececeesseeeeene eee nee sees ee eeeeeeeenseeeeeeeeeaeeeaeaeneneaeetneneeeneees 16 TI.1. MAKO SHARK GENERAL BEHAVIOR,...0c0cececeeeeeeeeeseeeesesaeeeeenenensases 16 INT.2. SIZE RELATED BEHAVIORsss scausas cases annxnts wexs oamees opnesninereaeeeveseverses23 TII.2.1. SHARKS SMALLER THAN 150 CM TL... ccc cee ecee eeeeeaee axed TH.2.1.1. MAKO 12 ARCHIVAL RECORD...csseceeeeeteeeneeeeneeeeeeenee ene27
TI.2.2. SHARKS BETWEEN 160 AND 180. CM TL... eeeeeee 36
IT2:2..1.. MAKO:1'5 ARCHIVAL RECORD i wxsssiy sca cs sxeremeromuseyead40
TI.2.3. SHARKS LARGER THAN 180 CM TL.... 1 49
TI.3. AREA RELATED BEHAVIOR...-..scsceeeeeeeeeeneeenseeeeenees 152 TIT.3.1. OREGONIAN PROVINCE. ...0cececeeeeneeeeeeeeneneneneeeneneusacesseeeets52 JII,3.2, SAN DIEGAN PROVINGE.» neercneesinnsilsS3 RU ERERRBRG RhinND slew A ee eR aEES 54 TY-3.3 CORTEZ PROVINGBasasssyine seeunavs ove ncexesaesnvanswmanavavnsruesereerens)O
TI.3.4. MEXICAN PROVINCE....
58
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TV.1. GENERAL BEHAVIOR...sc0eeeeeeeees 61
IV.2. SIZE RELATED BEHAVIOR... as63
xiii
LIST OF TABLES
Page
Table I. Details of the mako sharks tagged in the Southern California Bight and Baja California from June 2004 to January 2006... ccc cece eee ee ee eeeee eee ene ee ee eneeeeaeneenens 9
Table II. Geo - location error estimates depending on location class...:0eceeeeeee 15
xiv
LIST OF FIGURES
KV
LIST OF FIGURES (CONTINUES)
I. INTRODUCTION
Distribution patterns of animals are determined largely by habitat preference and
availability. Freon and Misund (1999) define habitat use as the place or environment in
which the animal lives and it is determined by a complex array of biotic and abiotic
factors. Habitat use and selection may be determined by the response of the animal to
abiotical factors such as temperature and light (Sims, 2003), but also by ecological factors
like food availability, competition, predation risk, and social and reproductive behaviors
(Heithaus et al., 2002). Therefore, habitat selection may be defined as the non random use
of a place resulting from the voluntary movements of an organism as a response to a wide
array of co-varying biotic and abiotic factors (Sims, 2003).
Little is known about the habitat use of most large marine pelagic predators.
Historically, pelagic animals have represented a great challenge for researchers due to their
size, speed and distribution along the vast oceanic habitat, and because it is difficult to
follow them without the appropriate instrumentation (Block,ef al, 2005).
One group oflarge pelagic predators that has been particularly difficult to study is
pelagic sharks. As with other organisms sharks may not be foundin all the habitats within
their range, but more likely they have particular habitats in which they spend mostof their
time (Simpfendorfer and Heupel, 2004).
The problems of identifying a species or individual’s preferred habitat can be
divided in two: 1) determining if habitats are used according to their availability; and 2)
While scientists have long been interested in the habitat use of marine sharks, it wasn’t until the late 1990’s that this importance was recognized by fishery managers (Simpfendorfer and Huepel, 2004). Recently, fishery managers and administrators have put extra effort into acquiring information regarding the habitat use of many directed or incidentally fished species (e.g. blue shark, thresher and mako sharks), and ofthose listed as endangered (e.g. whale shark, white shark and basking shark, amongothers).
Efforts to include more complex information on habitat use into fisheries management have been advanced as new tools have become available to study large pelagic fish. These include acoustic and satellite telemetry, and archival tags that have all advanced our ability to study the open-ocean ecosystem (Block, 2005). Development of electronic tagging and remote sensing technologies launched a new era for marine biologists. Modern tags contain powerful microprocessors (not only memory) and updated sensors that provide faster and more accurate sampling of movements and behaviors as well as the environment. In addition, remote sensing satellites provide global imagery with high resolution that allow for better integration of environmental data and that collected from the tagged animals. These new tools are generating advances in biology and improving our ability to answer ecological questions (Block, 2005).
The shortfin mako shark (/surus oxyrinchus, Rafinesque 1810), along with the great
white shark (Carcharodon carcharias) and porbeagle shark (Lamna nasus) belongs to
temperature of the surrounding environment (Compagno, 2002; Bernal e/ al., 2003a). This regional endothermy is advantageous for enhancing the function of the swimming, visual, digestive and nervous systems whenin cold waters at high latitudes or when diving below the thermocline (Compagno, 2002). These sharks mature at a total length around 1.8 m for males and 2.8 m for females (Mollet ef a/., 2000; Joung and Hsu, 2005) and have been estimated to live as long as 45 years (Cailliet et al., 1983). Large adult mako sharks feed mainly on fishes like swordfish, eels, bonitos, tunas and other sharks (California Department of Fish and Game, 2001), and as adults are top predators. Juvenile shortfin mako sharks feed mainly on cephalopods and small pelagic fish (Preti ef al., 2006).
The shortfin mako shark is an oceanic and near shore species, with a global distribution in all tropical and temperate waters (between 40° north and south latitudes).
They inhabit from surface waters down to 500 m deep and areas where surface water
temperature is around 16° C. The mako is thought to be one of the fastest and most active sharks (Compagno, 2002).
Shortfin mako sharks have slowly become an important specie in longline fisheries in many countries, switching from incidentally fished to target specie. Besides its value as food item, the shortfin mako shark’s reputation of a big fight when fished has made them valued and pursued by sport fishermen inspiring mako fishing tournaments around the world (Holts and Bedford, 1993).
Bedford (1993) carried out an acoustic tagging study of three juvenile mako sharks in the California Bight, finding no diel pattern in the vertical or horizontal movements, or association with islands, banks or any other bottom characteristics. They suggested that
makosharks in the California Bight have a wide habitat range, like makos in the Atlantic
Ocean, and that to identify any diel or island oriented movement pattern, it would be
necessary to expand the shark tracking time.
L1. HYPOTHESIS
Due to mako shark biological characteristics I present the following hypothesis:
The vertical and horizontal movements of tagged mako sharks are correlated with environmental conditions such as depth and temperature.
1.2. OBJECTIVES
1.2.1. Describe the vertical and horizontal movements using PAT and SPOTtags 1.2.2. Describe the habitat of mako sharks tagged in the Northeast Pacific
1.2.3. Determine the existence of temperature and depth preferences 1.2.4. Determine the presence of diel movements
Il MATERIALS AND METHODS
IL1. TAGGING PROCEDURE AND PROGRAMMING
A total of 24 mako sharks where tagged for this study. Twenty three mako sharks
were tagged during the National Oceanic & Atmospheric Administration (NOAA)
Southwest Fisheries Science Center’s (SWFSC) annual juvenile pelagic shark survey on
board the NOAA R/V David Starr Jordan between June 2004 and July 2005. Sharks were
caught using a 2 milestainless steel longline set for 3 hours in the top 50 meters of the
water column. Hooks were baited with Pacific mackerel (Scomber japonicus). Uninjured
sharks were taken to a special cradle at the rear of the vessel where a salt water hose was
placed inside the shark’s mouth to irrigate its gills and guarantee oxygen supply during the
tagging operation. A dark and moist cloth or towel was placed over the shark’s eyes to
keep the animal calm. Total (TL) or fork length (FL) was measured to the closest cm; sex
was also recorded. Sharks were tagged with one or two types of electronic tags as
described below. One additional mako shark was tagged during a trip conducted in January
and February 2006 on board the Mexican commercial F/V YUMANO.Sharks were caught
using monofilament longline (six hour soak), and hooks were baited with Pacific mackerel
and squid (Dosidicus gigas). Only one mako shark was healthy enough to be tagged. The
shark wasfirst brought on deck and then handled and tagged following the same protocol
used aboard the R/V David Starr Jordan.
Both Popup Archival Ttransmitting (PAT) and Smart Positioning or Temperature
Transmitting (SPOT) tags used were manufactured by Wildlife Computers (Redmond
studies because they provide data acquisition without the need of recapturing the tagged
fish. Also, the information is stored in hard memory and can be downloadedif the tag is
recovered. The PAT tags can record depth (measured from 0 to 1000m; with 0.5m
accuracy), temperature (measured from -40 to +60° C; with accuracy of 0.05° C), and light
level (measured in irradiance at a wavelength of 550 nanometers; dusk and dawn events
can be discriminated up to 300m deep in clear water conditions). At a user specified time
and date, the PAT corrodes the pin to whichthe tether is attached, releasing the tag from
the animal. The PAT then floats to surface and transmits the summarized information via
the Argos system. Service Argos provides the pop-off location with accuracy as good as
+350m. Daily longitude and latitude can be calculated from transmitted light level curves
by the researcher using WC-GPE,a software program developed by Wildlife Computers.
The program uses standard astronomical equations to determine longitude based on the
time of local noon or midnight, and latitude based on the day length. Longitude accuracyis
approximately +2 degree. Latitude accuracy depends upon both thelatitude and time ofthe
year. Best accuracies (+1 degree) are achieved at high latitudes near the solstices, and
worst occur near the equator near the equinoxes (+10 degrees, where and whenlatitude can
be calculated; Wildlife Computers, 2005). PAT tags were attached below thefirst dorsal
fin by making a shallow incision with a scalpel and inserting a stainless steel anchor into
the dorsal musculature. A plastic tie (zip tie) was used to keep the tag close to shark’s body
to reduce drag while swimming.
Smart Position or Temperature Transmitting (SPOT) tags are the smallest near
tags transmit the animal’s location via the Argos system with location accuracy up to +
150m (Wildlife Computers, 2005). SPOT tags were attached on thefirst dorsal fin by first
drilling 3 holes in the fin ('/4 inch drill bit) and then secured with nylon bolts and stainless
steel washers and nuts (Fig. 1). When possible, the hook was removedorelse the line was
cut close the hook. Afterwards, sharks were released and observed as they swam away
from the vessel. Tagging locations were recorded from the vessel’s global position system
(GPS). The process generally took less than 5 minutes. A total of 17 PAT and 22 SPOT
tags were deployed. Fifteen sharks were double tagged (PAT/SPOTpairs), seven sharks
were tagged with only a SPOT tag, and two sharks were tagged with only a PAT tag
(Table I).
Eight PAT tags were programmed to sample depth, temperature and light level
every minute and store the information to be sent via satellite as twelve hour bins. The
remaining nine were programmed to sample the same parameters every 30 seconds and
send twelve hour bins. The PAT tags were programmed to release from sharks either 180
or 210 days after deployment day. SPOT tags were programmedto transmit location every
10
Figure 1. A) PAT (P) and SPOT(S) tags attachedto ajuvenile mako shark; B) Recently tagged and released mako shark. Photos by Mark Conlin; courtesy ofNational Oceanic & Atmospheric Administration Fisheries.
Figura 1. A) Marcas PAT (P) y SPOT(S)fijadas en un tibur6n makojuvenil; B) Tiburén mako recién
11
IL2. DATA ACQUISITION AND PROCESSING 11.2.1. PAT DATA
Information transmitted via satellite is summarized according to the programmed intervals. All data from tag’s drifting period, on bottom or on land were excluded for any further analysis.
All satellite messages received by Argos in the form of “ds” or “prv” and archival records were analyzed. Twelve hour histograms of time spent at depth and temperature as well as each shark’s PAT depth and temperature profile (PDT) for 12 and 8 hour bins were extracted from data files using WC-AMP program. Archival records were extracted manually using Instrument Helper program in order to separate day and night time data appropriately according to day length variations due to seasonal changes. All data from PAT tags was separated in three size intervals: <150, 160 — 180 and > 180 cm TL to examinesize related behaviors. Further more, all information regarding depth, temperature and location was separated in four areas to examinearea related behaviors; these areas are: Oregonian Province; San Diegan Province; Cortez Province; and the Mexican Province. These areas were selected because of their special oceanographic and biogeographic
12
II.2.2 LIGHT LEVEL BASED GEO LOCATION FROM PAT TAGS
For sharks where only PAT tag data was available locations were estimated from light levels and sea surface temperature. Longitude was estimated from local time of dawn and dusk using the program WC-GPE from the tag manufacturer (Wildlife computers) which uses standard astronomical equations (Hill and Braun, 2001). For the latitude calibration we used only the tag deploymentlocation; sometimes we also had to adjust the cloud cover to make sure we hadthe best location fit. We had to hand select some of the light level points to improvelatitude uncertainty; if either half or the whole light curve had a doubtful longitude estimate often due to outlying light level data associated with greater depths, it was deleted. For those sharks that were not double tagged (n=2), we compared sea surface temperature (SST) satellite imagery with the SST recorded from the PATs to
improve the latitude estimates (Sims ef al., 2003; Dewar ef al., 2004; Teo ef al., 2004).
We used the temperature recorded by the PAT tag corresponding to the 0-5 m depth
interval as the SST forthe latitude improvement.
1.2.3. VERTICAL MOVEMENT ANALYZES
13
To examine potential differences in behaviors inshore and offshore, we separated
all depth/temperature data according to their distance to shore. A distance of 30 nm was
considered to be the boundary between coastal and oceanic environments based on the fact
that the continental platform along the Northeaster Pacific is in general narrow and
inclined with an average width of 20 km or 11 nm. This analysis was only conducted for
sharks carrying SPOT tags due to the high location accuracy.
To identify the presence of depth or temperature preferences we calculated the
depth and temperature in which each shark spent most time. Time at depth and temperature
modes were calculated using conditional statements in Microsoft ® Excel (2003). These
statements search for the highest bin value for each day; this value represents the depth
where the fish spent mosttime.
Full day maximum and minimum depths and temperatures, as well as daily average
depths and temperatures were calculated from the PAT’s Depth and Temperatureprofile
(PDT) data for each shark. The SST was obtained using a conditional statement than
14
The daily thermocline depth for each shark was estimated using the daily PDT records, by calculating the first derivative of temperature with depth using the formula:
At/Az = (Ta — Tm) / (n — mn);
where T, and T,, are the temperatures at the top (n) and bottom (m) of a given slice of the depth of the water. The maximumchange in temperature, represented by the maximum value of At/Az, is the defined thermocline (Carlson and Simpson, 1996). For the thermocline to be observed in the PDT record the shark had to move across the thermocline depth. All At/Az values for each day where plotted using Ocean Data View ® 3.2 (Schlitzer, 2006).
For the two recovered PAT tags we separated day and night time depth and temperatures depending on light level readings and time of sampling (data taken in 1 min intervals). Day length differed during tracking time due to seasonal changes. Also, light level readings were corrected for moon phases.
15
II.3. HORIZONTAL MOVEMENTS ANALYZES
11.3.1. SPOT DATA
Spot tag’s locations were filtered according to the Service Argos Inc. (2001) geo
location error estimate for each location class (Table II), keeping only the data for which
location error were less than 1 km (location classes 3 — 1). Using these filtered location
data we plotted the near real time horizontal movements for each shark with ArcGis
Software 9.2.
Table II. Geo - location error estimates depending on location class (Modified from Service Argos Inc,
2001).
Tabla II. Error estimadoen la localizaci6n asociado a la Clase de Localizacién (LC).
Location Class (LC) Location Accuracy (Lat/Long)
3 <150m
2 150 <x <350m
1 350 <x < 1000 m
0 > 1000 m
A Location not acquired
B Location not acquired
Locations for all sharks were combined by date to examine the presence of
seasonality in horizontal movements as well as differences between coastal and off-shore
behaviors. Kernel density was calculated using the daily averaged positions for all sharks
using the density toolbox included in ArcGis Software 9.2. The Kerneldensities were used
only as a toolto identify areas of high use and were graphically compared with primary
production imagery obtained by processing SST, chlorophyll a concentration and
photosynthetic active radiation (PAR) imagery with Windows Image Manager Program
6.45 (Kahru, 2006), were primary production was calculated using Morel - Berthon
16
II. RESULTS
TII.1. MAKO SHARK GENERAL BEHAVOIR
The 24 tagged sharks ranged in size from 114 to 281 cm TL; the male - female sex
tatio was 5:1. Based on the findings of Joung and Hsu (2005) twenty of the tagged sharks
were considered as juveniles. The largest female tagged was 177 cm TL. Weanalyzed data
from 13 PAT and 21 SPOTtags. Data from other 5 tags was not retrieved. Tracking days
ranged from 36 to 470; distances traveled from deployment to popup locations varied from
1,108 to 25,491 km; average speed for all sharks was 0.686 + 0.024 m s' (Table IID.
Sharks traveled as far north as the northern parts of Oregon; and as far south as the North
Equatorial current, around 13° 45.150'N and 120° 12.480'W (Fig. 2).
140°
110°
Figure 2. Locationsofthe 21 SPOT tagged makosharks from summer 2004 to fall 2006. Blackline represents the limit between coast and open ocean (55.5 km ~ 30 nm).
17 Table III. Total distance, maximum speed, minimum temperature and maximum depth experienced by 23 of 24 mako sharks from 2004 to 2006. Tabla III. Distancia Total, velocidad maxima, minimo de temperatura y maxima profundidad experimentadas por 23 tiburones durante 2004 a 2006. PAT SPOT Sex Total Length (cm) tracking tracking days days Shark Total Average speed (m/s) Distance (km) Max speed (m/s) +SE Max depth(m) Min Temp (°C)
Makol Mako2 Mako3 Mako4 Mako5 Mako6 Mako7 Mako8 Mako9 Makol0 Makoll Makol2 Makol3 Makol4 Makol5 Makol6 Makol7 Makol8 Makol9 Mako20 Mako22 Mako23 Mako24
186 182 364 13522.600 2.906 0.641+0.0249 360 78 142 36 157 3899.443 2.779 0.556+0.0375 268 8 187 225 217 8117.127 2.989 0.76440.0390 356 i 167 277 8079.510 2.769 0.71140.0277 186 470 25491.636 2.894 0.864+0.0222 191 403 15148.405 2.977 0.694+0.0263 151 313 9922.952 2.758 0.699+0.0282 168 123 20254.583 2.973 0.736+0.0219 133 311 7449.009 2.986 0.634+0.0314 152 377 10374.706 2.998 0.611+0.0265 164 233 15145.477 2.865 0.565+0.0226 114 104 82 2098.308 2.619 0.577£0.0477 332 8 177 125 395 9449.171 2.981 0.620+£0.0223 236 10 154 111 2650.505 2.756 0.542+0.0336 171 86 86 2119.114 2.798 0.586+£0.0476 188 10 125 130 127 4985.992 2.972 0.727+0.0225 304 154 415 3069.042 2.790 0.935+0.0410 150 185 242 9642.389 2.910 0.823+0.0203 304 177 180 237 11940.286 2.932 0.742+£0.0168 336 135 68 62 2921.225 2.879 0.831+0.0390 236 155 173 312 139. 27 240 160 79 76 1108.726 2.433 0.546+0.0554 124 12
© oN A 0
SSSSFSSSS4XSEHEHXSEHUSSZSSSSZSZEZ2
18
Time at depth data for all 13 sharks that carried PAT tags showedthat the juvenile
and adult mako sharks experienced depths from surface up to 356 m, but spent most of the
tracking time (95%) between surface and 150 m deep. Sharks spent most of time (95%) in
water temperatures between 12 and 22° C, even though they experienced temperatures as
low as 7° C; SST ranged from 10 to 27.5 ° C (Fig.3).
The location of 21 sharks showed a wide range of movement. Even though some
sharks tended to stay in the Southern California Bight (SCB) throughout the year (Fig. 4),
we observed a year round trend of near shore northward movement during summer and
fall; and southward in winter and spring (Fig. 5). These trends are confirmed when density
is compared with seasonal changes in primary production along the California Current
system (Fig. 6). Sharks moved along the coastline but also moved as far as 600 km from
19
§0-406 400-150 (a) wdeq 156-206200-250
06
(©)
250-306 >360aaa 22 21
>24 26
22-28
63)
19
20-22 18 18-20 7 0) 1S 16-18 16 14-16 <15 42-44 t r T 7 7 r t t 7 + 4012 oc0 O02 004 O06 G08 O10 O12 O14 O16 O18 6.20 (©) dues B10 Proportion (670 days)68 46 <4
Figure
4,
Kernel
density
of
the
average
daily
locations
for
21
sharks
from
June
2004
to
January
2006
tracked
a
cumulative
total
of
2,356
days.
Figura
4.
Densidad
Kernel
de
la
localizacién
diaria
promedio
de
21
tiburones
durante
Junio
2004
a
Enero
2006.
20
Summer 04 n=12
Winter 05 n=4
Ss
Summer 05 n=12 Winter 04 n=13 Fall 05 n=7 Cummulative Yi
1 10 15
Figure
6
Pele
ir
yok
lis)
WE
Mme
aamd
baat
Lena)
Nites
@
180
225
270
315
350
405
450
Seasonal
primary
productivity
as
aderived
chlorophyll
(C)
value
(g
C
m?
d’!)
within
the
California
Current
system.
Figura
6.
Produccion
primaria
estacional
dentro
del
Sistema
de
la
Corriente
de
California.
22,
23
TII.2. SIZE REALTED BEHAVIOR
III.2.1. SHARKS SMALLER THAN 150 cM TL (<150)
Six ofthe tagged sharks were less than 150 cm TL (Makos2, 9, 12, 16, 20 and 23)
and all exhibited the same trend of remaining in SCB and coast of California and Baja
California. Sharks concentrated mostly from Point Conception, CA, to San Quintin, Baja
California. Depth and temperature data from sharks less than 150 cm were obtained only
from two seasons, the summer andfall 2004 and 2005 (Fig. 7).
Figure 7. Kernel density of6 mako sharks smaller than 150 cm TL tracked a cumulative total of 739 days. Figura 7. Densidad Kernel de 6 tiburones mako menores a 150 cm LT, seguidos por un total acumulativo de
24
During tracking five of the six sharks remained 55% of time between surface and 5
m deep, while spending 30% ofthe track time between 5 and 50 m. Sharks spent 65% of
the track time above the thermocline (between 25 and 50 m deep). Water temperatures
experienced by these sharks ranged from 7 up to 26 °C, although sharks spent 81% of the
time in temperatures between 14 and 22 °C (Fig. 8). Temperature at depth profiles for 5 of
these 6 sharks showed a broad range of depths and temperatures during summerand fall
2004 and 2005 as well as the thermocline depth ranging from 25 to 100 m (Figs. 9a; 9b).
(A)
OS
6-10
10-60
50-100
100-150
Depth
(m)
180-200
200-250
250-300
>300
@)
72422-24 20-22 18-20 16-18 44-46 12-14 10-42 810 68 46
<4
Temp
(°
C}
0.0 04 02 03 04
Track time (proportion; 365 days)
Figure 8. Time spent at depth (A) and temperature (B)of five mako sharks less than 150 cm TL during summerandfall 2004 and 2005.
(uw) deg
25
Temperature
(°C)
os los 03
26
Temperature (°C) 08(uw) deg Co (uw) dea loz ot od IMako20 IMakp20 07/28 08/07 08/17 08/27 09/08 096 07/28 08/07 087 08/27 09/06 09/18 Temperature (?C)
8 04 os
27
TIL.2.1.1. MAKO12 ARCHIVAL RECORD
This 114 cm TL male shark was tagged on Jun 29 2004 and spent most of the track
time near the SCB, remaining mostly between surface and 60 m deep; water temperature
ranged from 8 to 24° C, spending most of time (60%) in waters between 16 and 24° C
during the 104 tracking days (Fig. 10). Highly significant differences in temperature and
depth between day and night for the full track time were found (depth ¢0.05, 14= 1.838; p<
0.001; temp 0.05, 14= 1.051; p< 0.001). Maximum depth during track was 332 m (average
depth = 57.08 + 1.57 m), with water temperature of 8° C. Makol2 madea total of 1667
dives, and spent a maximum time of 15 hours 59 minutes at a depth of 196 m; maximum
bottom time was 7 hours 39 minutes; average surface time was 32 minutes, with a
maximum value of 10 h 31 min. Mean temperature for the 104 days was 15° C, with
maximum temperature of 24° C. SST ranged from 16 to 24° C throughoutthe entire track
time. Maximum dive depths were always below the thermocline depth (approximately 50
m), although Mako12 remained most of the 104 days of tracking between 0 and 60 m deep
28 During summer months (July — September) Mako12 spent most of time (©60%) between surface and 5 m, with water temperatures that ranged from 8 to 24° C, but the shark spent most of time (>60%) between 16 and 24° C. On Fall (September — November), Makol2 spent most of time (>60%) between surface and 50 m deep; remaining most of time (60%) in waters between 16 and 20° C (Fig. 12). Differences in time spent at temperature or depth between day and night during the 53 days considered as Summer
time were found (depth 0.05, 14= 3.226; temp C008, 14= 1.242; p< 0.001); while there were
Depth
(m)
10
20 30 40 50 400 150 200 260 300 360 400
29
-0.8
(A) (B)
30
25
Cc
iH a
£20
5 e
15
Co day (5) day
HM night 10 HH night
t 1 + 1 r t T
0.0 a2 04 0.6 0.8 04 0.2 0.0 a2 04
Track time (proportion; 104 days
Figure 10. Time spent at depth (A) and temperature (B); location of Mako12 (C) during 104 days oftracking (Jun 29/04 — Nov 15/04).
©)
(A)
=
coal
400 08/07 08/27 09/16 10/06 10/26 e eote
0.4 SST 100 03 8Rg (ui) yydaq 02 300: Of‘DIA F120 W899
400: T + i 08/07 08/27 09/16 10/06 10/26 2004 085.
30
225 15400 150 200 250 300 350 >400
Depth
(m)
30
26
Temp
(°C) 8
a
31
(A) (cc
i
Hi HOH
roy HH
HoH IH
HH 4
KR I
H Co ay Co day
Summer(34/Jul - 22/Sept 04) Ha right Fall (23/Sept - 10/Nov 04) HE hight
08 ~06 04 0.2 0.0 02 04 06 08 1.8 -06 04 02 00 02 o4 06 08
(B) (@)
Eel
a)
I
td eay 4 (I day
Summer(34/Jul - 22/Sept 04) Pam rial Fall (23/Sept - 10/Nov04) HE ight
0.4 0.3 0.2 04 0.0 01 02 03 04.06 0.4 02 0.0 0.2 04 06 Track Time (proportion; 53 days) Track Time (proportion; 51 days)
Figure 12. Time at depth (A, C) and temperature (B, D); spent by Mako12 andlocation (E) during summer (green) and fall (orange) 2004.Figura 12. Tiempo a profundidad (A, C) y temperatura (B, D); localizacion (E)
32 Makol2 remained near the shore in two occasions. The first time (Jun 30 — Aug 18/04), it stayed in the southern region of the SBC spending most time between surface and 50 m in waters around 20° C, although it was exposed to temperatures lower than 14° C in depths exceeding 200 m. On the second occasion (Aug 24 — Sep 02/04) it remained north the Channel Islands, spending most time from surface to 100 m deep in water temperatures from 8 to 24° C (Fig. 13). Differences in time spent at depth and temperature between day and night during the 59 days of tracking considered as “in shore behavior”
where found (June 30 depth *¢0.05,14= 7.703, temp 0.05.12 0.0298, p< 0.001; August 24
depth y7o,05,14= 4.095, temp ¥0.0s,12= 1.322, p< 0.001).
During the 104 days of tracking Makol2 also made off shore incursions in two occasions. The first time (Aug 19 — Aug 23/04), this shark directed south from the Channel Islands and remained most of time (>60%) between surface and 10 m deep; water temperature ranged from 10 to 24° C, but the shark spent most time (>60%) in waters between 20 and 24° C. The second incursion (Sep 03 — Nov 10/04), Mako12 remained west from Point Conception, spending most of time between surface and 50 m deep andin water temperatures from 16 to 20° C (Fig. 14). There were differences in time at depth or temperature between day and night during the 73 days considered as “offshore behavior” (August 19 depth ¢0.05,14= 1.257, temp °0.05,19= 0.2657; p< 0.001; September 03 depth
¥0.05,14= 2.673, temp 0.05,12= 1.981; p< 0.001).
Differences between coastal and oceanic behaviors were found (depth °o05,13=
33
Depth
(m)
3
Jun/30 - Aug/18/04
(A)
Aug/24 - Sep/02/04
©
Co day HB night
0.8 06 -0.4 02 00 06 0.80.6 0.4 02 04 Os
Temp
(°C)
Ba
10 4
Jun/30 - Aug/18/04 i daynight
Aug/24 - Sep/02/04 HE right
0.6 0.4 0.2 0.0 02 04 0.60.8 06 -0.4 -0.2
Track Time (proportion; 10 days)
0.0 0.2 04 06 08
©
Figure 13. Mako12 time spent at depth (A, C) and temperature (B, D); location (E) during Jun 30 — Aug 18/04 (1) and Aug 24 — Sep 02/04 (2) inshore incursions. Figura 13. Tiempo a profundidad (A, C) y
34
0
1(A)
(©)
§ 10 20
= 30
£ 40
& 50
& 400
a
150
200
250
300
a0 dey Oey
*409 Aug/19 - Aug/23/04 HE right Sep/03 - Nov/10/04 right
1 1 1 1 r 1 r T 1 + 1 r +
0.4 -0.3 -0.2 -0.4 o1 02 03 04 06 06 0.4 0.2 0.0 02 04 06 0.8
>26
26
24
22
20
Oo 18
‘16
12 10 &
: TA dey (oo day
<4) Aug/19 - Aug/23/04 Ha night Sep/03 - Nov/10/04 TEBE night
I 1 1 r + T T T + 1 1
-0.6 -0.4 -0.2 0.2 04 og 04 0.3 0.2 -0.1 o.0 O41 a2 03 04
Track Time (proportion; 5 days) Track Time (proportion, 68 days)
=
(E)
Figure 14. Mako12 time spent at depth (A, C) and temperature (B, D); location (E) during Aug 19 — Aug 23/04 (1) and Sep 03 — Nov 10/4 (2) offshore incursions.
35
There was an apparent late coupling of Mako12 seasonal movements related to a
lag in time of biomass accumulation in primary production hotspots inside the SCB.
Makol2 remained inside the SCB during summer when the highest primary production
could be found north Point Conception; afterwardsit traveled outside the SCB during fall
whenthere was no high primary production around thearea the shark spent time (Fig. 15).
(A)
Point Conception, CA.
90SeaWiFs: Annual Primary Productioi135 180 225 270
gcim2)
CeeKy 0 405 450
(B) Point Conception, CA.
Figure 15. Summer(A) and Fall (B) 2004 primary production at the area Mako12 spent mosttime.
36
T].2.2. SHARKS BETWEEN 160 AND 180 cM TL (160 — 180)
Eleven ofthe tagged sharks were between 160 and 180 cm TL (Makos7, 8, 10, 11,
13, 14, 15, 18, 19, 22 and 24). These sharks remained mostly between Point Conception
and San Quintin, traveling farther north and south (up to Oregon and south Revillagigedo
Island, respectively) but also traveling farther from shore up to 4,600 km (Fig. 16). Data
from these sharks was gathered from summer 2005 to spring 2006.
Figure 16. Kernel density of 11 mako sharks between 160 and 180 cm TL tracked a cumulative total of2,366 days.
Figura 16. Densidad Kernelde 11 tiburones makoentre 160 y 180 cm LT,seguidosporun total acumulativo
37
Throughout the tracking period, all sharks remained 85% of time between surface
and 50 m deep, performing vertical incursions of more than 300 m less than 1% of the
track time. Water temperatures ranged from 7 up to more than 24 °C; even though sharks
spent 95% of time in water temperatures between 12 and 20 °C (Fig. 17). Temperature at
depth profiles show the seasonal changes in temperature and thermocline depth (between
50 and 100 m) in the broad area were these sharks traveled (Fig. 18a; 18b).
(A)
os 5-10 10-50 50-400 100-150
Depth
(m)
150-200 200-250 250-300 >300
224
(B)
22-24 A
20-22 48-20 16-18 14-16 12-14 10-12 8-10 6-8 46 <4
Temp
(°
C)
0.0 ot 0.2 0.3 o4
Track time (proportion; 643 days)
Figure 17. Time spent at depth (A) and temperature (B)for six of eleven mako sharks from summer2005 to spring 2006.
Temperature (°C) (uy) uidog 25 (uy) dea IMako19
O78 (uy) dea
|
we
Tas
12725 09/08 10/26 12725 7/09 os (wi) deg Mako22(Mako22 06723 ove 09/06 2005 Temperature (° €) 1215 06/23 O78 09/06 10/26 16 At/Az 08 (u) deg (w) neg 300° [Mako24 IMako24 i |
a= i é
40
TL.2.2.1. MAKO15 ARCHIVAL RECORD
This 171 cm TL female shark was tagged on November 18 2004 andtraveled south as far as Magdalena Bay (Baja California Sur, Mex.), remaining most of the track time near the coast of the Vizcaino Peninsula. During the 86 daysoftracking, it spent most of time between surface and 100 m deep; water temperature ranged from 10 to 24° C, spending most of time (>60%) in waters between 16 and 18° C (Fig. 19). Differences in temperature and depth between day and night were found for the entire track time (depth
0.05, 14= 0.348, temp 0.05, 2= 0.0216; p< 0.0001). Maximum depth during track was 192
m (average depth= 34.15 + 1.07 m), with water temperature of 13.2° C. Mako15 made 721 vertical incursions, and spent a maximum time of 21 hours 56 minutes at a depth of 64 m;
maximum bottom time was 4 hours 8min; average surface time was 13 minutes, with a
maximum of 3 h 44 minutes. Mean temperature for the 86 days was 18° C, with minimum
and maximum temperatures of 10 and 27° C, respectively. SST ranged from 16 to 27° C throughoutthe entire track time. Maximum dive depths were always below the thermocline depth, although Mako15 remained most of tracking time between 0 and 120 m deep (Fig.
41
During Fall (November — December) Mako15 spent most of time (60%) between
50 and 100 m, with water temperatures that ranged from 10 to 20° C, but shark spent most
time (60%) between 14 and 16° C. On Winter (December — February), Mako15 spent
most of time (>60%) between 5 and 100 m deep; remaining most of time (60%) in waters
between 14 and 16° C (Fig. 21). We found highly significant differences in time spent at
temperature or depth between day and night during the 40 days considered as Fall (depth
0.08, 14= 0.219; temp 0.05, p= 0.312; p< 0.0001) and the 46 days considered as Winter
42
Depth
(m)
o (A) >2 (B)
| n 26
to 4
2 20
30 in
40 Oo 18
50 a 16
400 £5 ou
10°) min R
an my 40
250 8
300 5
ne cay TC tay
>400 I night <4 IEE night
03 02 “04 oo on 02 03008 06402
Track time (proportion; 86 days)
©
Figure 19. Time spentat depth (A) and temperature (B); location ofMako15 (C) during 86 days oftracking
(Nov 18/04 Feb 09/05).
Temperature (° C) 25
8
(ui) yrdaq 15 300 1043
‘m21A e7eCE020|
(A)
115 12005 12/25 0114 02/03 e At/Az as tH fe SST 100 0.3g
(u) ndeg
02 300 04 ‘Nala280 U8820@)
NAS 12/05 12/25 01/14 02/03 105 ond 0203OIA 00 118930.
Depth
(m)
Temp
(°C)
44
‘
(A)
©
4. 10 20 30 40 50 100
150 4
am |
250 4
300 4
350-4 5 tay tay
400 FALL (11/Nov - 21/Dic 04) Bm night WINTER (22/Dic - 12/Feb 05) HE nicht
04 -02 00 02 a4 -0.4 0.2 0.0 0.2 0.4
726426 4 9) 4 @)
244 fl
= Pb
ay a
18 4 4
ie | 0
44 4 n
124 4
104
84 4
64 4
(J aay 7 day
<4) FALL (11/Nov- 21/Dic 04) Gam ist |) WINTER (22/Die- 12/Feb 05) Ma nie
0.8 06 0.4 0.2 0.0 02 04 06 0.81.0 0.8 0.6 -04 -0.2 0.0 02 04 oO6 08 1.0
Track Time (proportion; 40 days) Track Time (proportion; 46 days)
(E)
Figure 21. Time at depth (A, C) and temperature (B, D) spent by Mako15 and location (E) during Fall (orange) 2004 and Winter (dark blue) 2004/2005.
45
Mako15 was tagged offshore, approximately 30nm from Point Conception, CA.
While traveling south, this shark remained offshore 17 days and spent most time from
surface to 100 m deep, in water temperatures from 14 to 18° C. During its second offshore
incursion on January 29/05, Mako15 spent most of the 14 days of tracking time form 0 to 5
m deep, occasionally diving as deep as 180 m. Water temperature ranged from 10 to 27° C,
but Makol5 spent most time between 14 and 18° C (Fig. 22). There were differences in
time spent at temperature and depth between day and night for November (depth 0.05, M4=
0.702; temp 0.05, 13= 0.502; p< 0.0001) and January (depth 0.05, a= 1.735; temp 0.05, B=
0.032; p< 0.0001) offshore incursions.
Makol5 remained near shore 54 days (from December 06/04 to January 28/05)
front of Vizcaino Peninsula, Baja California. During these 54 days it spent most time
between surface and 100m deep in water temperatures of 14-16° C; water temperature
ranged from 10 to 20° C (Fig. 23). Differences in time spent at temperature and depth
between day and night were found (depth 0.05, 14= 0.411; temp 0.05, 13= 0.067; p<
46
(B)
Depth
(m)
s
400
150 200
260
300
350 Co tay (day
>400 Nov/19 - Dec/05/04 I night Jan/29/05 - Feb/12/05 [ED night
03 0.2 -01 0.0 O41 02 Os 0.4 02 0.0 02 04 o6
@)
>30 : (O}
8B
24 |
20 4
184 - 4
164 4
14 4
12 |
10 4
8 4
6 Cody {7 7 day
<44 Nov/19 - Dec/05/04 Mmm night | Jan/29/05 - Feb/12/05 I night
Temp
(°
C)
T r T T T
08 06 04 -02 0.0 02 04 06 010.8 -0.6 -0.4 -0.2 0.0 0.2 a4 0.8 08
Track Time (proportion; 17 days) Track Time (proportion; 15 days)
()
Figure 22. Mako15 time spent at depth (A, C) and temperature (B, D); location (E) during Nov 19 — Dec 05/04 (1) and Jan 29 — Feb 12/05 (2) offshore incursions. Figura 22. Tiempo a profundidad(A, C) y
Depth
(rn)
47
0 (A)) 20 (B)
1 28
a 26
10 4
20 2
30 20 |
“ g 18
60 S
400 2 16oO
150 oH Fr 14
200 I 12
250 rH 10
300 8
a0 5 dey 8 (dey
>400 Dec/06/04 - Jan/28/05 TE right <4] Dec/06/04 - Jan/28/05 HE night,
= * z v T T T T T T T T
0.3 0.2 O41 0.0 O4 02 03 100-08 -06 -04 02 009 02 O04 06 O8 10
©
Figure 23. Time spent at depth (A) and temperature (B) during 54 days oftracking (Dec 06/04 — Jan 28/05).Location of Mako15 (C); circle represents inshore incursion.
48
There was also an apparentlate coupling of Mako15 seasonal movements related to
the lag of biomass accumulation in primary production hotspots along the coast of Baja
California. Mako15 traveled south and far from shore during fall when the highest primary
production could be found near Vizcaino and Magdalena Bays; during winter it traveled
briefly near shore when there was no high primary production around the area the shark
remained for sometime (Fig. 24).
EVEekee eS
SLI Meck (sd 274 20d Ue eC ce A)
Figure 24. Fall (A) and Winter (B) 2004 primary production at the area Mako15 spent mosttime. Figura 24, Producciénprimaria en el otofio (A) e invierno (B) en el area donde el Mako15 permanecié mas
49
TII.2.3. SHARKS LARGER THAN 180 CM TL (> 180)
Four sharks were larger than 180 cm TL (Makos 1, 3, 5 and 6). These sharks
exhibited the same trend of staying mainly between Point Conception and San Quintin,
although their distribution is slightly shifted towards the north. In general, these sharks
moved farther away from the coast (as far as 5,000 km from shore) and also spent more
time in the offshore areas (Fig. 25).
Figure 25. Kernel density of4 makosharks larger than 180 cm TL tracked a cumulativetotal of 1,454 days. Figura 25. Densidad Kernel de 4 tiburones mako mayores de 180 cm LT, seguidos un total acumulativo de
50
Timeat depth and temperature data was gathered only from Makos 1 and 3; these
adult male sharks were tracked for a combined total of 407 days from summer 2004
through January 2005. Throughout the track these sharks remained 90% of the time
between surface and 50 m deep; these sharks performed vertical incursions below 100 m
less than 10% of the time. Also, sharks spent 80% of the track time in waters with
temperatures between 14 and >24 °C (Fig. 26). Temperature and depth profiles from these
sharks reflect the wide range of depths and temperatures that they experienced wile being
tracked (Fig. 27). Differences in time spent at depth and temperature between all size
classes were not found (70.05, 9= 2.161; p> 0.05).
5
S10 10-50 60-100
100-150
150-200
Depth
(m)
200-250
P24
18-20 16-18 14-16 42-44 10-12 8-10 68 +6 <4
Temp
°C)
0.00 0.05 0.10 015 0,20 0,28 0,30 0.35
Tracktime (proportion; 407 days)
Figure 26. Time spent at depth (A) and temperature (B) of 2 mako sharks from summer 2004 to January 2005. Figura 26. Tiempo a profundidad (A) y temperatura (B) experimentadas por 2 makos durante el verano
52
ILL.3. AREA RELATED BEHAVIOR
III.3.1. OREGONIAN PROVINCE
High location density was found north Point Conception. Mako sharks tended to
remain within 370 km from shore (200 nm) highly concentrated within 185 km (100 nm)
from shore (Fig. 28). Temperature in the area ranged from 7 to 16 °C, while vertical
incursions where not deeper than 270 m. Sharks spent 60% of the time inside the
Oregonian Province between surface waters and 5 m deep and less than 5% diving in
waters deeper than 150 m; sharks spent most of the time (80%) in water temperatures
between 12 and 18° C (Fig. 29).
Figure 28. Kernel density ofdaily locations for 13 sharks (pooled years) in the Oregonian Province for a
cumulative total of 380 days. Solid lines represent 55.5 (30 nm); 185 (100 nm); 370 (200 nm); and 925 km
(500 nm) from shore, respectively.