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FLAMMANG, BROOKE E. 2005. Masters of Science, Moss Landing Marine Laboratories, California State University, Monterey Bay, 85 pp.

Thesis Title: DISTRIBUTION AND REPRODUCTIVE ECOLOGY OF THREE SPECIES OF DEEP-SEA CATSHARKS, APRISTURUS BRUNNEUS, A. KAMPAE, AND PARMATURUS XANIURUS, OF THE EASTERN NORTH PACIFIC.

Abstract - Information on the distribution and reproduction of the catsharks Apristurus brunneus, A. kampae and Parmaturus xaniurus was generated from specimens collected by fishery independent survey cruises from June 2001 through October 2004 between northern Washington to San Diego, California. Longline catches consisted mainly of P. xaniurus, with occasional catch of gravid female A. brunneus. Conversely, trawl catches consisted mainly of Apristurus species. Apristurus brunneus was typically found between 300 and 942 m, while A. kampae occurred > 1,000 m depth. Parmaturus xaniurus was caught between 300 and 550 m depth. Egg cases of A. brunneus and P. xaniurus were collected in trawl surveys and observed in video footage taken by remotely operated vehicle. These egg cases were located in specific sites on areas of high vertical relief at 300 to 400 m depth. Total length at first, 50% and 100% maturity were determined for males and females of all three species. At higher latitudes, A. brunneus and P. xaniurus reached sexual maturity at larger sizes. Apristurus brunneus and P. xaniurus reproduce year-round based on the occurrence of gravid females and the lack of seasonal variation in gonadosomatic (GSI) and hepatosomatic indices (HSI) for both males and females. Gravid A. kampae females were found from July through December. The egg case of A. kampae is described and its morphology compared to the egg cases of A. brunneus, P. xaniurus, and other Apristurus species.

PEREZ, COLLEENA R. 2005. Masters of Science, Moss Landing Marine Laboratories, California State University, Monterey Bay, 95 pp.

Thesis Title: AGE, GROWTH, AND REPRODUCTION OF THE SANDPAPER SKATE, BATHYRAJA KINCAIDII (GARMAN, 1908) IN THE EASTERN NORTH PACIFIC OCEAN.

Abstract - The sandpaper skate, Bathyraja kincaidii, is commonly taken as bycatch in trawl fisheries off central California although little life history information is known for this species. To assess age, growth and reproduction, 506 Bathyraja kincaidii were collected from commercial samplers, museum collections, and monthly trawl and slope surveys conducted by the National Marine Fisheries Service since January 2002. Sexes were equally represented, with females comprising 48.8% and males 51.2% of samples collected. Females ranged from 199 to 610 and males from 195 to 635 mm total length (TL). For age and growth analysis, 188 sectioned vertebrae were read 3 times and APE (0.10), CV (0.09) and D (0.06) precision values calculated. Ages were assigned based on agreement of at least two independent estimates, with an additional read used to establish agreement if necessary. Both marginal increment analysis and centrum edge analysis failed to show significant documentation of growth band formation periodicity. Caudal thorns could not verify age estimates from vertebrae due to within-sample variability of age assignments, variability of caudal thorn growth compared with TL, large bias of age for thorns compared with vertebrae, and unacceptable precision values for APE (14.5), CV (19.70) and D (11.40). Therefore, they were designated unreliable for age and growth analysis of B. kincaidii. Age estimates from vertebral centra indicate a minimum longevity of 17 years for female and 18 years for male B. kincaidii. Females (L∞ = 537.3 mm; k = 0.237; to = -1.629; n = 100) grew faster but males (L∞ = 580.2 mm; k = 0.185; to = -2.530; n = 90) reached a larger size. Maximum likelihood ratio indicated no significant difference (p > 0.05) between male and female von Bertalanffy growth parameters, and combined sexes produced values of L∞ = 557.8 mm and k = 0.207. Females first mature at 450 mm (~4 years), while males first mature 440 mm TL, ~1 year earlier. However, size and estimated age at 50% maturity was similar between sexes: 467 mm and 7.1 years for females and 492 mm and 7.5 years for males. GSI and HSI values indicate a slight, but not statistically significant seasonal increase in reproductive effort and the occurrence of inactive females throughout the year indicates a resting period following parturition.

TREJO, TONATIUH. 2005. Masters of Science, Moss Landing Marine Laboratories, California State University, Monterey Bay.

Thesis Title: GLOBAL PHYLOGEOGRAPHY OF THRESHER SHARKS (ALOPIAS SPP.) INFERRED FROM MITOCHONDRIAL DNA CONTROL REGION SEQUENCES.

Abstract - The family Alopiidae is comprised of three species: the pelagic (Alopias pelagicus), bigeye (A. superciliosus), and common (A. vulpinus) thresher sharks. Alopias pelagicus occurs only in the Indian and Pacific Oceans, while the other two species are distributed worldwide. Despite growing conservation concerns, genetic relatedness among thresher shark populations is poorly known. I examined the phylogeographic structure of each species using DNA sequences from the mitochondrial control region. Alopias samples were collected from the East and West coasts of the United States, Gulf of Mexico, Gulf of California, Clipperton Atoll, Guatemala, Ecuador, Hawaii, Taiwan, Indonesia, New Caledonia, New Zealand, South Africa and France. Despite their high dispersal potential, my data indicate limited gene flow among thresher shark populations, but phylogeographic patterns differ among species. Gene flow in A. pelagicus is limited across the Pacific Ocean, but is extensive among locations in both the eastern and western Pacific. In A. superciliosus, shallow population structure was detected among samples from Indo-Pacific and Atlantic populations, but not among specimens taken from locations spanning the Indo-Pacific Ocean. Results for A. vulpinus indicate genetic heterogeneity among almost all sampled populations, both within and between the Atlantic and Indo-Pacific oceans. Taken together, my data suggest that intraspecific biological and ecological differences among thresher sharks may be sufficient to cause variable patterns of interspecific genetic population structure. This study also highlights the need for international cooperation for the conservation and management of thresher sharks.

HUMAN, BRETT A. 2003. Doctor of Philosophy, University of Cape Town, Cape Town, South Africa, 213 pp.

Dissertation Title: TAXONOMY AND MOLECULAR PHYLOGENY OF SOME SOUTHERN AFRICAN CATSHARKS (SCYLIORHINIDAE: CHONDRICHTHYES).

This thesis examines the alpha level taxonomy and molecular phylogeny of some catsharks that are found in southern Africa, many of which are endemic to the region, with some extending into east Africa. Many of the species examined here are abundant and yet are poorly known in all aspects of their biology. The present study aims to rectify the taxonomic problems that have plagued some of the species under review.

This study reviews the genera Haploblepharus, Holohalaelurus and Poroderma, all of which have taxa endemic to southern Africa. In all of the taxonomic reviews, an extensive list of over one hundred morphometric and meristic measures have been used in regression analyses and multigroup principal component analyses (MPCA) in an attempt to separate species from species complexes. MPCA is demonstrated to be a useful tool in species separation, and this study is the first to use multivariate statistics for chondrichthyan species discrimination. Novel species identification keys have been constructed for each of these genera, and a comprehensive review of the taxonomy (including type material and synonyms), biogeography and biology of all taxa is presented.

The genus Haploblepharus is endemic to southern Africa and is diagnosed as containing four taxa, including H. edwardsii, H. fuscus, H. pictus, and a newly described taxon, H. kistnasamyi. This review offers the first comprehensive description of the variable colour pattern of H. pictus. The revision also highlights misidentification problems of that species with H. edwardsii, and offers revised distributions of H. edwardsii and H. pictus, with a considerable range extension for the latter. A neotype has been designated for H. edwardsii.

The genus Holohalaelurus is an obscure, although sometimes abundant, deepwater group of sharks endemic to southern and east Africa. This review is the first dedicated review of the genus. The general neglect of this genus has resulted in a confusing history of type material, with some type series containing multiple species, and these issues have been resolved here. Two taxa were recognised prior to this study, and as a result of this revision, there are now four taxa recognised, including H. melanostigma, H. punctatus, H. regani and a newly described taxon, H. grennian. In addition to this, H. polystigma is determined to be a synonym of H. punctatus, and two subspecies of H. regani, H. r. regani and H. r. favus, are recognised and described. Neotypes for H. punctatus and H. regani have been designated. The review also highlights an apparent population decline of H. punctatus and H. r. favus from the KwaZulu-Natal - southern Mozambique region.

Poroderma is endemic to southern Africa, as identified in the current study, and consists of P. africanum and P. pantherinum. P. marleyi is shown to be a synonym of P. pantherinum, and a new colour form of P. pantherinum is described. This review is the first to offer a comprehensive description of the colour variation exhibited by P. pantherinum.

In addition to the morphological taxonomy, a molecular phylogenetic investigation was conducted to examine phylogenetic relationships between various members of the catsharks, and is the largest chondrichthyan data set yet analysed, consisting of nearly 130 000 nucleotides. Three mitochondrial DNA genes were used to construct the phylogenies, cytochrome b, NADH-2 and NADH-4, resulting in 41 sequences from 18 taxa being novel to this study. These sequences were either used separately or were combined into a single data set. A number of different tree constructing algorithms were used, including parsimony with bootstrapping, maximum likelihood via quartet puzzling, and Bayesian inference using a Metropolis-coupled Markov chain Monte Carlo search strategy. Results of the three methods are compared. A comprehensive review of the methodology of molecular phylogeny is also provided and examines some of the potential problems that may be encountered in molecular phylogenetic analyses.

DAINTY, ALISON M. 2002. Masters of Science, University of Cape Town, 108 pp.

Thesis Title: BIOLOGY AND ECOLOGY OF FOUR CATSHARK SPECIES IN THE SOUTHWESTERN CAPE, SOUTH AFRICA.

Abstract - This is the first biological study of four endemic catshark species, Haploblepharus edwardsii, H. pictus, Poroderma africanum, and P. pantherinum, from the southwestern Cape. Diets of two hundred and forty-one specimens were examined via stomach contents. Prey were sorted and identified to the lowest possible taxon. An index of Relative Importance (IRI = %F (%N + %V)) was used to determine the importance of prey items in the catsharks' diets. The most important prey groups were crustaceans (IRI = 6125), annelids (IRI = 4177) and teleosts (IRI = 1859) for H. edwardsii; crustaceans (IRI = 7656), teleosts (IRI = 4154) and mollusks (IRI = 152) for H. pictus; teleosts (IRI = 9694), mollusks (IRI = 784) and crustaceans (IRI = 612) for P. africanum; and mollusks (IRI = 3367) and teleosts (IRI = 2574) for P. pantherinum. Males and females of each species ate similar prey, although the importance of some prey varied. The most important prey taxa were annelids (IRI = 5740) for female and crustaceans (IRI = 7568) for male H. edwardsii; crustaceans for both male (IRI = 9300) and female (IRI = 5963) H. pictus; teleosts for both sexes of P. africanum (male, IRI = 5394; female, IRI = 4760); and mollusks for both male (IRI = 3180) and female (IRI = 2250) P. pantherinum. There was a general decrease of importance of teleosts with increasing size for all four catshark species. An increase of importance of crustaceans with increasing size was apparent for H. pictus and P. africanum. The importance of mollusks was independent of size for H. pictus, although their importance increased with increasing size for both Poroderma species. H. edwardsii, H. pictus and P. africanum all seem to be generalist feeders, preying upon a variety of food sources, while P. pantherinum has a more specific diet, feeding almost exclusively on teleosts and mollusks.

In order to estimate gastric evacuation rates of the three catshark species, Poroderma africanum, P. pantherinum, and Haplobelpharus pictus were maintained in laboratory conditions and fed meals equaling 1% of their body weight (BW). Food items included clipfish, Clinus spp., octopus, Octopus vulgaris, and sandprawn, Callianassa kraussi. Catsharks were sacrificed at intervals after feeding to measure rates of gastric emptying. Data were fitted to various models to describe the decrease of stomach contents with time. The generalized additive linear model provided the best fit for all food types. Evacuation rates varied between prey types for the three shark species, with octopus (19.5-24.5 hours) taking the least time for 95% of the meal to be evacuated, followed by fish (36-48 hours) and prawn (70 hours - H. pictus only). For most data, the model revealed an initial period of maximal evacuation, followed by a decreased rate until complete evacuation. Some data indicated a 'plateau' phase, where the emptying rate decreased after the initial maximum period of evacuation and then continued again in an increased rate until complete evacuation. There were no significant differences (p<0.001) of gastric evacuation rates between species fed the same prey item. Passage of food from the stomachs of these three shark species is slow relative to teleost fishes, but comparable to that recorded in other elasmobranch species.

Life history information was collected on 86 Poroderma africanum, 71 P. pantherinum, 68 Haploblepharus edwardsii and 116 H. pictus from various sites in the southwestern Cape, South Africa, between February 2000 and May 2002. Gonad characteristics and embryo development suggest a year-round breeding season for all four species. The slopes of the length-weight curves were significantly different (p<0.001) between sexes for both Poroderma species and for H. edwardsii, but there was no significant difference (p>0.05) between sexes for H. pictus. Total length at 50% maturity was 857 mm for male P. africanum and 866 mm for females (91% asymptotic length for both sexes), 590 mm (85% asymptotic length). For male P. pantherinum and 595 mm for females (85% asymptotic length). For H. edwardsii, sex-combined data reveal a 351 mm TL at 50% maturity (71% asymptotic length). Male H. pictus reach 50% maturity at 503 mm TL (78% asymptotic length) in contrast to 491 mm (77% asymptotic length) for females. Resin embedding techniques revealed translucent and opaque growth band formation on sectioned vertebrae for the four catshark species. Based on three tagged/recaptured P. africanum individuals and the good fits of the Schnute growth model to the length/age data, growth band formation was considered annual for all four shark species. Ages calculated for length at 50% maturity were 24 years for P. africanum, 17 years for P. pantherinum, 7 years for H. edwardsii and 15 years for H. pictus.

FREER, DAVID W.L. 1992. Masters of Science, University of Cape Town, 103 pp.

Thesis Title: THE COMMERCIAL FISHERY FOR SHARKS IN THE SOUTH-WESTERN CAPE, WITH AN ANALYSIS OF THE BIOLOGY OF THE TWO PRINCIPAL TARGET SPECIES, CALLORHINCHUS CAPENSIS DUMERIL AND GALEORHINUS GALEUS LINN.

Abstract - The South African shark fishery began in World War 2, based on a demand for shark liver oil. The initial landings are estimated at 3750 tons per annum, but have since declined to approximately 820 tons of shark, principally Galeorhinus galeus, with an additional 800 tons of Callorhinus capensis. The fishery for the later species has largely only developed since 1980.

The fisheries for both of the principal species are dependent for their commercial success on fishing schools of breeding aggregations and in both cases the catch is mainly taken in breeding and nursery areas.

G. galeus is a largely ichthyophagous species, which forms schools of fish similar size. After sexual maturity, which is reached at a minimum TL of 1 278 mm (8.5y) for males, and a minimum TL of 1 371 mm (9.9y) for females, these schools further assort to include only mature fish of one sex. They are highly mobile and may be migratory. Fecundity is low in newly sexually mature fish but gradually increases with increasing size, although a mathematical relationship for this could not be established. The maximum number of pups recorded in this study was 20. Age was established by counts of depositional rings in vertebral centra, and the growth rate described by the formula:

L(t) = 1601.378016 (1-e^{-0.16207 (t+1.327677)}).

C. capensis, which is common in catches on soft substrates from 1-366 m, has a catholic diet dominated by invertebrate benthic organisms. High concentrations of the fish only occur inshore (<50 m). These aggregations consist of juveniles and post-sexual maturity fish migrating inshore annually to breed. Breeding occurs all year round with a peak in summer. Sexual maturity (50%) is attained at FL 429 mm in males (3.17y) and FL 494 mm in females (4.2y). Fecundity is also relatively low with a maximum of 22 viable eggs being recorded. Age is estimated by counts of serially deposited cones of dentine in the dorsal spine. Age estimates are validated by cone margin characteristics and by length-frequency analysis. Growth curves are described by the formulae:

L(t) = 1989.37537 (1-e^{0.051465(t+0.605681) 0.5201111}) for females and

L(t) = 658.64095(1-e^{0.170824(t+0.72077) 0.593056}) for males.

The shark fishery is a complex and multi-species, and controls cannot be applied to it as a single entity. While the fishery for C. capensis appears to be less likely to collapse, the fishery for other shark species is rapidly declining. The principal problem is that both fisheries utilize breeding fish and operate principally in nursery areas.

WALTER, J.P. 1988. BSc (Honors) in Ichthyology, Rhodes University, 30 pp.

Thesis Title: PRELIMINARY ESTIMATES OF AGE OF THE BRONZE WHALER CARCHARHINUS BRACHYURUS (CHONDRICHTHYES: CARCHARHINIDAE) FROM SOUTHERN AFRICA, WITH A REVIEW OF SOME LIFE HISTORY PARAMETERS.

Abstract - Counts of growth bands in sectioned vertebral centra were used to estimate the ages of 61 bronze whalers Carcharhinus brachyurus collected between March 1984 and June 1988 from southern Africa. Estimates of Von Bertalanffy parameters for the observed data were: L oo = 384.8, K = 0.0385, to = -3,477. The to value overestimates the gestation, which is thought to be between 8 and 24 months. Growth in bronze whalers appears to be slower than in any Carcharhinus spp. previously studied. Maximum size recorded during this study was 294 cm total length (TL) for a male and 288 cm TL for a female, and the maximum ages recorded were 30 and 25 years, respectively. Age at sexual maturity has been calculated at 13-19 years for males and 19-20 years for females. Differential mortality rates appear to operate on juveniles (Lee's phenomenon). Arguments are presented that indicate two separate populations: one distributed from the Western Cape eastwards and the other from just south of Walvis Bay northwards. The slow growth rate, low fecundity and high age at sexual maturity make the bronze whaler extremely vulnerable to overfishing.