The goal of this study was to determine the energetic requirements of juvenile scalloped hammerhead sharks (Sphyrna lewini) in Kaneohe Bay, Oahu, Hawaii using a multidisciplinary approach. A large flume/respirometer (635 1) was constructed to determine the critical swimming speeds (Ucrit )' swimming kinematics (tailbeat frequency, tailbeat amplitude, and stride length), and oxygen consumption rates (V02 ) of juvenile sharks over a range of swimming speeds (U). Swimming kinematics were also compared with unconstrained sharks in a seawater pond. These experiments indicated that tailbeat frequency (TBF) and water temperature could be used as a predictor of U and V02 for free-swimming sharks in the field; however, the flume affected the sharks' swimming kinematics at slow speeds. The flume and pond kinematic comparisons were used to correct for flume effects on sharks' V02. An acoustic tailbeat-sensing transmitter was designed and constructed to quantify activity and energy consumption of free-swimming hammerhead shark pups in Kaneohe Bay. Sharks with transmitters behaved similarly to uninstrumented sharks, but incurred a 28% increase in cost of transport due to increased drag from the transmitters. These data were used to correct for the effects of the transmitter on freeswimming sharks in the field. Sharks tracked in Kaneohe Bay with tailbeat transmitters exhibited increased U during dawn and dusk, while sharks tracked in the warmer summer months had higher activity rates and metabolic rates (MR) than a shark tracked during the winter. Sharks tracked in this study had higher MR than those measured for other species of tropical sharks and, as a result, require higher daily rations. Low and negative growth rates determined from sharks in the Bay and declining catch rates over the season suggest that a large percentage of the pups in Kaneohe Bay may starve as the result of their high metabolic requirements. Although prey do not appear to be li~itingi lack of foraging experience compounded by a high daily metabolic demand may explain why sharks lose weight during summer months. Those pups that survive the winter experience lower MR due to seasonal temperature decline and less competition as the result of high neonatal mortality. / x, 130 leaves, bound : ill. (some col.) ; 29 cm. / Missing page 74.

Thesis (MSc)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: Smoothhound sharks Mustelus mustelus (Chondrichthyes: Triakidae) were conditioned to associate a compound auditory and electrical conditioned stimulus (CS) using the presentation of food as the unconditioned stimulus (US). This was done to investigate the general conditioning process of sharks, specifically the use of conditioned stimuli, the time frame required for conditioning, the retention of conditioned responses and the individual learning capabilities of sharks in classical conditioning experiments. Conditioning was done in two CS experiment replicates, in which the CS and the US were paired to elicit a conditioned response (CR: entering of a feeding area). Shark behaviour in these replicates was compared with those of sharks in a CS control. In the CS control, the CS and US were not paired; consequently no CS-US association was formed. In contrast, half of the sharks in the 1st and 2nd CS replicates formed the conditioned CS-US association after five and six days of conditioning training, respectively. This conditioned association was also retained over a two-month rest period. However the rate of conditioning of sharks varied, which was thought to be due to differences in motivational drives, particularly hunger. These experiments demonstrated that classical conditioning could provide a mechanism whereby smooth hound sharks can adapt to utilise new food sources. However these experiments could not demonstrate whether auditory or electrical cues are more biological relevant signallers of the presence of food for smooth hound sharks. According to the "belonging ness" phenomenon, for conditioning to be successful, the CS should be biologically relevant to the US. Therefore by comparisons of the conditioning success with different conditioned stimuli, the biological relevance of each CS can be determined. To determine the biological relevance of each component of the compound CS, an auditory or electrical CS was paired with the presentation of food (US), in separate experiments. The conditioned CS-US association formed in the majority of the sharks after 60 and 57 conditioning trials in the auditory CS and electrical CS experiment, respectively. This suggests that both auditory and electrical cues are biologically relevant signallers of food, facilitating the oppurtunistic feeding behaviour of smoothhound sharks. However, after five days of conditioning, conditioning with the electrical CS had proceeded further and the electrical CS-US association was stronger than the auditory CS-US association. This indicates that electrical cues are more biologically relevant due to past feeding experiences. Thus, classical conditioning during past feeding experiences can influence the feeding behaviour of smooth hound sharks. / AFRIKAANSE OPSOMMING: Gladde-hondhaaie Muste/us muste/us (Chondrichthyes: Triakidae) is gekonditioneer om "n gekombineerde klank en elektriese konditionerings stimulus (CS) met voedsel, die ongekonditioneerde stimulus (US) te assosieer. Dit is gedoen om die konditionerings proses, spesifiek die gebruik van konditionerings stimuli, tyd benodig vir konditionering, behoud van die gekonditioneerde gedrag en individuele leer-vermoëens van haaie in klassieke konditionerings eksperimente te ondersoek. Konditionering is gedoen in twee CS eksperiment replikate, waarin die CS en die US saam aangebied is, om "n konditionerings reaksie (CR: om in 'n voedings area in te beweeg) teweeg te bring. Die gedrag van haaie in die CS replikate is vergelyk met die van haaie in "n CS kontrole. In die CS kontrole is die CS en die US nie saam aangebied nie en gevolglik is geen gekonditioneerde CS-US assosiasie gevorm nie. Daarenteen is die CS-US assosiasie by die helfte van die haaie in die 1st en 2de CS replikate gevorm, na vyf en ses dae, onderskeidelik. Hierdie gekonditioneerde CS-US assosiasie het selfs behoue gebly na 'n twee maande rus periode. Die tempo van konditionering het egter verskil, moontlik a. g. v. motiverings verskille, veral hongerte. Hierdie eksperimente het gedemonstreer dat klassieke konditionering kan dien as 'n meganisme waarmee gladde-hondhaaie kan aanpas om nuwe voedsel bronne te benut. Hierdie eksperimente kon egter nie demonstreer óf klank stimuli óf elektriese stimuli meer biologiese relevante seine van die teenwoordighied van voesel is vir gladdehondhaaie nie. Volgens die "belonging ness" verskynsel, moet die CS biologies relevant to die US wees, vir konditionering om suksesvol te wees. Dus kan die biologiese relevansie van verskillende konditionerings stimuli bepaal word deur die konditionerings sukses van elke CS te vegelyk. Om die meer biologiese relevante komponent van die gekombineerde CS te bepaal, is 'n klank of elektriese CS saam met voedsel aangebied in aparte eksperimente. Die gekonditioneerse CS-US assosiasie is gevorm by die meeste van die haaie na 60 en 57 konditionerings proeflopies in die klank en elektriese CS eksperimente, onderskeidelik. Hierdie resultate dui daarop dat beide klank en elektriese stimuli biologies relevante siene van voedsel is, wat die oppurtunistiese voedings wyse van gladde-hondhaaie fasiliteer. Konditionering met die elektriese CS het egter verder gevorder en die elektriese CS-US assosiasie was sterker as die klank CSUS assosiasie na vyf dae van konditionering. Dus, mag elektriese stimuli meer biologies relevant wees weens vorige voedings ervaringe. Dit illustreer dat klasseke konditionering tydens vorige voedings ervaringe die voedings gedrag van gladde-hondhaaie kan beinvloed.

Heading on microfiche: Fitzgerald, Timothy Patrick. Thesis (M.S.)--University of Hawaii at Manoa, 2002. Includes bibliographical references (leaves 45-50). Also available on microfiche.

The blacknose shark (Carcharhinus acronotus) is a common small coastal shark species found in nearshore waters along the southeast coast of the United States, from North Carolina into the Gulf of Mexico and extending further south into the Bahamas. There has been some debate in recent years over the reproductive periodicity of C. acronotus in waters off the U.S. coast. Earlier studies have suggested that Gulf C. acronotus reproduce on an annual basis whereas the Atlantic populations of this species may reproduce biennially. Additionally, there have been no known studies on the diet of C. acronotus. The goal of the present study was to re-evaluate the reproductive biology of the Atlantic populations of C. acronotus with the intent on clarifying discrepancies in reproduction as well as provide information on dietary trends. This was accomplished by examining male and female reproductive tracts and gut contents in animals caught throughout the Atlantic range of C. acronotus. Based on these data, spermatogenesis occurs between late May to early July with peak sperm production occurring in June and July. In females, follicular development is complete by late June-early July with ovulation occurring shortly afterwards. Mating occurs between mid-June and early July based on the presence of fresh mating scars on females captured during this time. Current data suggests that gestation begins late July with parturition occurring late May to early June the following year. As observed in earlier studies, reproductive periodicity appears to be largely biennial. However, evidence for concurrent follicular development and pregnancy was observed in several females, suggesting that at least a portion of the Atlantic population may reproduce on an annual basis. Dietary data shows a dominance of teleost prey items in the diets of C. acronotus with scianids making up the majority of the identifiable teleosts.