Tarpons E-Book

Stephen Spotte

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 750

Veröffentlichungsjahr: 2016

Beschreibung

Stephen Spotte, Mote Marine Laboratory, Sarasota, Florida, USA Tarpons arose from an ancient lineage, and just two species exist today, confined to the tropics and subtropics: Megalops atlanticus in the western and eastern Atlantic and Megalops cyprinoides distributed widely across the Indo-West Pacific. The Atlantic tarpon is considered king of the saltwater sport fishes and supports a multi-billion dollar recreational fishery in the U.S. alone. The Pacific tarpon, which is much smaller, is less valued by anglers. Both have limited commercial value but offer considerable potential for future aquaculture because of their hardiness, rapid growth, and ease of adaptation to captivity. This book is the latest and most thorough text on the biology, ecology, and fisheries (sport and commercial) of tarpons. The chapters comprise clear, intricate discourses on such subjects as early development and metamorphosis, population genetics, anatomical and physiological features and adaptations, migrations, reproductive biology, and culminate with a concise overview of the world's tarpon fisheries. A comprehensive appendix includes Spotte's original translations of important papers published previously by others in Spanish and Portuguese and unavailable until now to English readers. Tarpons: Biology, Ecology, Fisheries will be of considerable interest and use to fishery and research biologists, marine conservationists, aquaculturists, and informed anglers

Leseprobe

Tarpons

Biology, Ecology, Fisheries

Stephen Spotte

Mote Marine LaboratorySarasota, Florida, USA

This edition first published 2016, © 2016 by John Wiley & Sons, Ltd

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Library of Congress Cataloging-in-Publication Data

Names: Spotte, Stephen, author.Title: Tarpons : biology, ecology, fisheries / Stephen Spotte.Description: Chichester, UK ; Hoboken, NJ : John Wiley & Sons, 2016. | Includes bibliographical references and index.

Identifiers: LCCN 2016003051| ISBN 9781119185499 (cloth) | ISBN 9781119185703 (epub)Subjects: LCSH: Tarpon. | Tarpon fisheries.Classification: LCC QL638.M33 S66 2016 | DDC 597.5/7–dc23LC record available at http://lccn.loc.gov/2016003051

A catalogue record for this book is available from the British Library.

Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books.

Cover image: Atlantic Tarpon © 1992, Diane Rome Peebles

Notes

1

See, for example:

http://www.catalogueoflife.org/col/details/species/id/17963572;

http://eol.org/pages/339927/names/common_names;

http://www.catalogueoflife.org/col/search/all/key/Megalops

2

 http://www.ticotimes.net/2011/07/06/tarpon-on-the-pacific-coast-you-betcha

. Downloaded 18 July 2015.

Acknowledgements

I thank the authors and publishers who allowed me to reproduce their figures and tables, and I thank Mote Marine Laboratory for use of facilities. I am grateful to Patricia E. Anyanwu of the Nigerian Institute for Oceanography and Marine Research for information on aquaculture of Atlantic tarpons, Michael Spotte for assisting with preparation of the figures, and Lucia Spotte for her patience and good humor while this work progressed. Special thanks is extended to Alyson Gamble, former Librarian at Mote’s Arthur Vining Davis Library and Archives for her unwavering enthusiasm about all things academic, and for energetically tracking down obscure references, pursuing some of them literally to the ends of the Earth.

Symbols and abbreviations

≈

approximately

<

less than

≠

unequal

>

greater than

≤

less than or equal to

≥

greater than or equal to

°C

degree(s) Centigrade

μ

micro

μm

micrometer (micron)

μmol

micromole

A

age (days)

ABO

air-breathing organ (physostomous swim bladder)

AC(s)

accessory cell(s)

ASB

aquatic surface-breathing

bp

(years) before present

CC(s)

chloride cell(s)

CFTR

cystic fibrosis transmembrane conductance regulator

CI

confidence interval (statistics)

cm

centimeter(s)

COX2

cyclooxygenase type 2

d

day(s)

df

degrees of freedom (statistics)

DOM

dissolved organic matter

dph

day(s) post-hatch

F

fecundity

f

ab

air-breathing frequency (per unit time)

f

H

heart rate (beats per unit time)

fl

femtoliter(s) (10

–15

l)

FL

fork length

g

gram(s)

G

growth (somatic)

GH

growth hormone

GSI

gonadal-somatic index

H

body height at its highest point

h

hour(s)

HA

H

+

-ATPase

Hb

deoxygenated hemoglobin (g/l)

HbO

2

oxygenated hemoglobin (g/l)

Hct

hematocrit (%)

HL

head length

H

O

mean observed heterozygosity

H

S

genetic diversity value

1

IGF-1

insulin-like growth factor 1

in.

inch(es)

kg

kilogram(s)

kPa

kilopascal(s)

L

body length (as FL, NL, SL, or TL)

L

liter(s)

lb

pound(s)

m

meter(s)

M

molar

MCH

mean cell hemoglobin (pg)

MCHC

mean corpuscular hemoglobin concentration (g/l)

MCV

mean corpuscular volume (fl)

min

minute(s)

mL

milliliter(s)

mm

millimeter(s)

mmol

millimole

O

2air

rate of oxygen uptake from air or ABO (mL/kg/min

O

2w

rate of oxygen uptake from water (mol/kg/min)

mol

mole

mOsm

milliosmole

MRC(s)

mitochondria-rich cell(s)

mRNA

messenger ribonucleic acid

ms

millisecond(s)

n

sample size

ng

nanogram

NHE

Na

+

/H

+

exchanger

NKA

Na

+

/K

+

-ATPase

NKA1

secretory form of NKA

NKCC

Na

+

/K

+

/2Cl

–

co-transporter

NKCC1

secretory isoform of NKCC

NL

notochord length

Osm

osmole

OSTF1

osmotic transcription factor 1

O

W

Otolith weight

oz

ounce

P

partial pressure

p

probability

P

50

P

O

2

at which 50% of Hb is bound to O

2

(HbO

2

)

P

a

partial pressure in arterial blood

Pa

pascal(s)

PAT(s)

pop-up archival transmitting tag(s)

pg

picogram (10

–12

g)

pH

cv

caudal venous pH

ppt

parts per thousand

P

v

partial pressure in venous blood

PVC(s)

pavement cell(s)

P

w

partial pressure in water

Q&c.dotab;

cardiac output (ml/min/kg)

r

2

coefficient of determination

RBC

red blood cells (10

6

/μl)

Rh(cg)

rhesus glycoproteins

Rhag

Rh-associated glycoprotein (ammonia transporter)

Rhbg

Rh-associated glycoprotein (ammonia transporter)

Rhcg

Rh-associated glycoprotein (ammonia transporter)

RSI

ram-suction index

S

salinity (mg/kg of seawater)

s

second(s)

S

A

absolute salinity scale (mg/kg of seawater)

SA

body surface area

SD

standard deviation

SE

standard error (slope of the regression)

SEM

standard error of the mean

SEM

standard error of the mean

SL

standard length

S

P

practical salinity scale (no units)

Su

Survivorship

TF2B

(osmotic) transcription factor 2B

TL

total length

TTPG

time to peak gape

U

crit

critical swimming speed (

l

/s)

V

ab

volume of a single breath of air

V

ABO

ABO volume (ml/kg)

vol%

vol/total vol × 100

V

R

(aquatic) ventilation rate (opercular pumps/min)

V

S

cardiac stroke volume (ml)

W

body weight, or mass (g)

W

r

relative weight (g)

y

year(s)

∑

sum

mean, or average

Z

Rayleigh’s test of circular distributions

Note

1

Nei’s unbiased gene diversity across all loci.

CHAPTER 1Development

1.1 Introduction

The developmental biology of tarpons is so unusual that it seems a fitting subject for the opening chapter. I had originally intended to present the ontogeny of Atlantic and Pacific tarpons side by side, with salient features and timing emphasized at least partly in tabular form, but inconsistencies in the literature made it impossible. Specimens in the various reports were often measured at different lengths and unknown ages. Although captive rearing eliminates the age problem, it introduces confounding factors that can compromise normal rates of growth and development. Then, too, descriptions ranged in quality from detailed to superficial. Taxonomists sometimes favored particular characters, relegating others to lesser status or ignoring them. In short, I could not get comparative descriptions to line up without generalizing, which would have diluted the entire effort. What I present is therefore detailed, but in narrative form, with the two species treated separately.

Nonetheless, the pattern of their ontogeny is similar. The descriptions presented follow staging systems devised in the 1960s and 1970s by Brazilian and US scientists for Atlantic tarpons. Those for the Pacific species are less detailed and cohesive. The objective is to offer a detailed summary of tarpon ontogeny book-ended by separate sections devoted to just the leptocephalus larva.

1.2 The tarpon leptocephalus

There was a time when nobody knew what young tarpons looked like, but some still claimed to have seen them. Among the many tall tales is this whopper recorded in a letter from Charles H. Townsend to Mr. Grant and reproduced by Beebe (1928: 230). Townsend was traveling to the Galápagos Islands to capture giant tortoises, probably for the New York Zoological Society’s Bronx Zoo, when he penned this:

“In conversation with Mr. S. A. Venable of the Zone Police Force [Panamá Canal Zone Police], an experienced [Atlantic] tarpon fisherman, I was informed that the fish is viviparous. He has repeatedly observed the females seeking shallow water, generally less than 4 feet deep, where a continuous stream of young fish was poured from her vent, the young being apparently little more than ¼-inch long. The young immediately seek refuge in groups, under the large scales of the mother, each scale standing outward at an angle of probably 30°. The young clustered in these scale shelters as thickly as they could. Mr. Venable’s many observations lead him to believe that the young shelter under the scales ten days or more, when they are ¾-inch long. The mother soon rids herself of the young by shaking herself and by leaping.”

Probably because the smallest tarpons he ever saw were juveniles, taxidermist and sportsman Victor Brown of Everglades City, Florida thought they hatch fully formed. In a letter to Kaplan (1937: 91), Brown wrote: “The newly spawned tarpons, 1 to 3 inches long, immediately commence to work their way entirely out of salt water into fresh water streams, into the multitude of small creeks and canals, some going as far inland as 25 miles from the Gulf [of Mexico].”

Contrary to these kinds of statements, baby tarpons do not emerge as miniature adults. They hatch from fertilized eggs as yolk-sac larvae before morphing into leptocephali, larval forms unique to relatively few species of fishes (Hulet and Robins 1989; Inoue et al. 2004; Wang et al. 2003). Greenwood et al. (1966) established the superorder Elopomorpha based on representatives of all its subgroups having leptocephalus larvae (Fig. 1.1). A leptocephalus is a bizarre shape-shifting creature, laterally compressed, transparent with a mucinous pouch, and described variously as ribbon-, band-, or leaf-shaped. Elopomorpha is a monophyletic group, the leptocephalus an elopomorph synapomorphy. Order Elopiformes (tarpons and ladyfishes) occupies the most basal place in elopomorph phylogeny, Albuliformes and a clade consisting of Anguilliformes and Saccopharyngiformes making up a sister group (Fig. 1.2