Gerald L. Crow

Fusarium solani Fungal Infection of the Lateral Line Canal System in Captive Scalloped Hammerhead Sharks (Sphyma lewini) in Hawaii

Two of five scalloped hammerhead sharks (Sphyrna lewini) captured May 1987 in Hawaii (USA) developed granulomatous exudative mycotic dermatitis localized in the lateral line canal system. The lesion initially was noted in the cephalic canals, but over a period of months extended into the lateral canal. Fusarium solani and Vibrio spp. were isolated from the canal exudate of both sharks. Bacterial colonies were not observed in the canal walls or surrounding tissues. Fusarium solani infection resulted in a chronic physical and behavioral deterioration of the two sharks; one shark was euthanized in September 1988 and the other in July 1989. This is the first report of Fusarium solani infection in the lateral line canal system and the third account in hammerhead sharks.

Relationship of Water Chemistry to Serum ThyroidHormones in Captive Sharks with Goitres

Captive whitetip reef sharks, Triaenodon obesus,at Sea Life Park (SLP) Hawaii, Waimanalo, Hawaii develop goitre, whereas, T. obesus at the Waikiki Aquarium (WAQ), Honolulu,Hawaii do not develop goitre. To determine theeffects of natural concentrations of iodine on thereduction of goitre, two sharks from SLP with goitrewere placed in an enclosed coastal lagoon with naturalseawater. Using ultrasound measurements the twogoitres were initially 11.4 cm and 14.6 cm in depthand after 3 months decreased to 4.7 cm and 5.7 cm. Radioimmunoassay analysis of the thyroid hormoneT3 sera concentrations were initially 0.22 ng/mland 0.33 ng/ml and increased to 1.84 ng/ml after beingplaced in the lagoon. Sera T4 were initially0.93 ng/ml and 0.99 ng/ml and increased dramaticallyto 17 ng/ml and 56 ng/ml. Over the six month samplingperiod, two resident sharks in the lagoon with normalthyroids had sera T3 concentrations from 0.89ng/ml to 1.1 ng/ml, and sera T4 concentrationsfrom 3.1 ng/ml to 7.9 ng/ml. The hypothyroidcondition in the SLP goitred-sharks is likely linkedto the low environmental iodide (<0.005 μM), andhigh nitrate (111 μM) of SLP water. The WAQwell-water facility was characterized by anoxic waterwith high iodide (0.60 μM), total iodine (1.90μM), and typical nitrate (24.6 μM)concentrations of interstitial groundwater. Thedifference of iodide concentration of SLP and WAQ tankwater (<0.005 μM versus 0.60 μM) wasdirectly related to the hydrogeology of the well-watersources. To avoid goitre in marine aquarium systems,we recommend maintaining iodide concentrations of atleast 0.15 μM.

Histological Assessment of Goiters in Elasmobranch Fishes

Abstract Twelve thyroid glands from free-living (n = 3) and captive (n = 9) elasmobranch fishes were investigated. Histological observation of the thyroids revealed two euthyroid glands, one case of mild chronic thyroiditis, three diffuse hyperplastic goiters, three diffuse colloid goiters, and three multinodular colloid goiters. The term goiter best describes the thyroid enlargement that results from hyperplasia and hypertrophy. Although elasmobranch goiters are typically linked to low aquatic iodine concentrations, iodine deficiency alone does not explain all of the observed thyroid conditions. Diffuse hyperplastic goiters typically result from either iodine deficiency or goitrogenic release of thyroglobulin from the follicle. Colloid goiters result from fluctuating iodine concentrations or goitrogenic agents that block the release of iodine from the thyroid gland. Although nitrate is a potential goitrogenic agent in aquaria, research indicates that nitrate interferes with the uptake and retention of io...

Long-term fluctuations in circalunar Beach aggregations of the box jellyfish Alatina moseri in Hawaii, with links to environmental variability.

The box jellyfish Alatina moseri forms monthly aggregations at Waikiki Beach 8–12 days after each full moon, posing a recurrent hazard to swimmers due to painful stings. We present an analysis of long-term (14 years: Jan 1998– Dec 2011) changes in box jellyfish abundance at Waikiki Beach. We tested the relationship of beach counts to climate and biogeochemical variables over time in the North Pacific Sub-tropical Gyre (NPSG). Generalized Additive Models (GAM), Change-Point Analysis (CPA), and General Regression Models (GRM) were used to characterize patterns in box jellyfish arrival at Waikiki Beach 8–12 days following 173 consecutive full moons. Variation in box jellyfish abundance lacked seasonality, but exhibited dramatic differences among months and among years, and followed an oscillating pattern with significant periods of increase (1998–2001; 2006–2011) and decrease (2001–2006). Of three climatic and 12 biogeochemical variables examined, box jellyfish showed a strong, positive relationship with primary production, >2 mm zooplankton biomass, and the North Pacific Gyre Oscillation (NPGO) index. It is clear that that the moon cycle plays a key role in synchronizing timing of the arrival of Alatina moseri medusae to shore. We propose that bottom-up processes, likely initiated by inter-annual regional climatic fluctuations influence primary production, secondary production, and ultimately regulate food availability, and are therefore important in controlling the inter-annual changes in box jellyfish abundance observed at Waikiki Beach.

First record of the squaloid sharkScymnodon squamulosus from the Hawaiian Islands

T he genus Scymnodon Bocage & Capello, 1864 belongs to the family Squalidae and is distinguished from other similar genera by the presence of upper teeth that are much longer midway along each side of the jaw than either toward the center of the mouth or its outer corners (Bigelow and Sehroeder, 1957). Bigelow and Schroeder (1957) recognized three species of Scymnodon: ringens Bocage & Capello, 1864, obscurus Vaillant, 1888, and squamulosus Gtinther, 1877. They differentiated between squamulosus and obseurus by the presence of transverse ridges on the dermal denticles of obscurus and their absence from squamulosus. Yano and Tanaka (1984) discovered that denticles of type specimens of squamulosus also had transverse ridges and they considered obscurus as a junior synonym of squamulosus. Yano and Tanaka (1984) included S. plunketi Waite, 1900 in this genus and described a new species, S. ichiharai. Taniuchi and Garrick (1986) grouped ringens, plunketi, ichiharai, and S. macracanthus Regan, 1906 in the genus Scymnodon, and resurrected the genus Zameus Jordan & Fowler, 1903, for squamulosus. Compagno (1984), Compagno et al. (1989, 1991) and Ebert et al. (1992) have retained the use of Scymnodon squamulosus. We follow Compagno (1984) and others in use of the genus Scymnodon. Scymnodon squamulosus, the velvet dogfish, has a fairly wide distribution along continental margins of tropical and temperate waters, with records from both the western Atlantic (Gulf of Mexico, Surinam, and Brazil) and the eastern Atlantic (Iceland to Senegal, and southern Africa) (Krefft, 1980; Compagno, 1984; Compagno et al., 1991). These sharks were reported from the Indian Ocean off southern Africa and western Australia (Bass et al., 1976; Shcherbachev, 1987; Last and Stevens, 1994). Pacific records include the South China Sea, Australia, New Zealand, Chile and Japan (Chu and Meng, 1982; Paulin et al. 1989; Melendez, 1991; Nakaya and Shirai, 1992). We report the first occurrence of S. squamulosus in the central Pacific and compare the morphometrics and reproductive condition of our specimens with those collected elsewhere.