Jeffrey C. Carrier

Albion College - retired · Biology

Elasmobranchs have elaborate organ systems for reproduction and many have complex reproductive life histories, but we are just beginning to understand that elasmobranchs may also exhibit involved pre-copulatory and copulatory and group behaviors. Shark, skate and ray behavior has been generally dismissed as unsophisticated by both biologists and no...

Elasmobranchs have elaborate organ systems for reproduction and many have complex reproductive life histories, but we are just beginning to understand that elasmobranchs may also exhibit involved pre-copulatory group courtship, mating and copulatory behaviors . Shark, skate and ray behavior has been generally dismissed as unsophisticated by both bi...

Understanding shark mating dynamics and mating site use may be vital to species management. The Dry Tortugas courtship and mating ground (DTCMG) has been known as a mating site for nurse sharks, Ginglymostoma cirratum, since 1895. In a 30-yr (1992-2021) study we have documented long-term site fidelity to this area with data from 137 adult sharks (8...

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

Decades of overexploitation have devastated shark populations, leaving considerable doubt as to their ecological status1,2. Yet much of what is known about sharks has been inferred from catch records in industrial fisheries, whereas far less information is available about sharks that live in coastal habitats³. Here we address this knowledge gap usi...

Given the conservation status and ecological, cultural, and commercial importance of chondrichthyan fishes, it is valuable to evaluate the extent to which research attention is spread across taxa and geographic locations and to assess the degree to which scientific research is appropriately addressing the challenges they face. Here we review trends...

The remarkable pace of advancements in technology, particularly in the last two decades, has contributed to the development of a toolbox that greatly enhances the range of investigations into the biology and life history of elasmobranchs. In our preface to The Biology of Sharks and Their Relatives in 2004, Jack Musick, Mike Heithaus and I hinted at...

Nurse sharks have not previously been known to migrate. Nurse sharks of the Dry Tortugas (DRTO) mating population have a highly predictable periodic residency cycle, returning to the Dry Tortugas Courtship and Mating Ground (DTCMG) annually (males) or bi- to triennially (females) during the June/July mating season. For 23 years we have followed the...

Polyandry has been demonstrated in a number of shark species. Studies based on a small number of loci typically estimate the minimum number of sires, which may be much lower than the actual number of sires due to the sharing of alleles by parents. We genotyped three litters of Nurse Shark (Ginglymostoma cirratum) ranging in size from 29 to 39 pups...

Little is known about the reproductive strategies and mating behaviour of most sharks. Understanding mating behaviour is important as it can determine reproductive success and possibly rates of multiple paternity and fecundity. Additionally, some sharks appear to have specific habitat requirements for mating activities. We tested the utility of a 3...

Sharks are top predators in many marine ecosystems. Despite recent concerns over declines in shark populations, studies of shark communities in coastal habitats are limited. We used drumlines and longlines to determine shark community composition and habitat affinities in the Florida Keys, USA. Community composition varied among habitats. Catch rat...

Print versions of presentations given by practitioners of animal-borne imaging research at the ABI Symposium held at National Geographic in 2007.

Crittercam is an animal-borne imaging and environmental data-logging instrument used to study large vertebrates in aquatic habitats. This paper describes an advanced Crittercam system that records video, audio and environmental data to solid-state digital media. This fifth generation (“GenV”) system is smaller, much more rugged and user-friendly, a...

A 12-year study of nurse shark Ginglymostoma cirratum reproduction in the islands of the Dry Tortugas, Florida has shown continued use of a 0.8-square-hectare shallow lagoon by sharks in all life stages from neonate through adult. Adults breed here every year during the June and July mating season. Juveniles use the same lagoon until they are about...

We analysed video records of three mating events involving nine free-living whitetip reef sharks in Cocos Islands, Costa Rica to examine reproductive behaviour in this species. We describe several behaviours never before documented in this species, and four behaviours never before documented in any elasmobranch. Here, we also present the first hypo...

The elasmobranchs have had an incredibly long evolutionary history: more than 400 million years. During this extensive period elasmobranchs separately evolved many adaptations such as exquisite senses and complex reproductive modes that rival those of the most advanced tetrapods. In this chapter we review the reproductive adaptations of the elasmob...

Over a period of 3 years, five reproductively active female nurse sharks (Ginglymostoma cirratum) from a wild, actively mating population of nurse sharks were captured, confined, and periodically examined through the course of gestation to determine the gestation period and characterize paternity. In the final year of the study, candidate animals w...

Elasmobranch reproductive behavior has been inferred from freshly caught specimens, laboratory examinations of reproductive structures and function, or determined from direct observations of captive or free swimming wild animals. Several general behaviors have been described including seasonal sexual segregation, courtship and copulation. Courtship...

The nurse shark (Ginglymostoma cirratum) is a common resident of Florida and Caribbean waters. In spite of its prevalence, details of nurse shark life history and ecology are not well known. Ongoing studies have identified a population that undergoes mating and parturition in one specific site in the Florida Keys. Our tagging, observation, and film...

Fifty mating events in free-living nurse sharks (Ginglymostoma cirratum) were observed over a nine-day period in the Dry Tortugas island cluster in the Florida Keys. Four stages of mating were identified: precoupling, coupling, positioning and alignment, and insertion and copulation. Copulation was observed and filmed in four of the mating events....

Growth rates determined from recapture of free-ranging nurse sharks (Ginglymostoma cirratum) averaged 13.1 ± 9.5 cm/yr and 2.3 ± 1.3 kg/yr based upon recapture of 44 tagged animals (28.9% recovery) with an average at-large interval of 247 d (range: 5-876 d), and an average size at tagging of 126.6 cm TL and 9.8 kg body mass. Growth measurements on...

Seventy nurse sharks (Ginglymostoma cirratum) were tagged and released from Big Pine Key, Florida with combinations of stainless steel barbed tags, plastic barbed tags and modified Carlin disc tags. Twenty percent of the tagged sharks were recovered; 35% of the animals tagged with only stainless steel barbed tags were recovered; 21% of those tagged...

Ginglymostoma cirratum, were tagged and released with combinations of stainless steel barbed tags, plastic barbed tags, and modified Carlin disc tags. Twenty percent of the tagged sharks were recovered; 35% of the animals tagged with only stainless steel barbed tags were recovered; 21% of those tagged with both plastic barbed tags and Carlin disc t...

(1) The marine teleost fish, Lagodon rhomboides, can only tolerate fresh water (5 mM Na) if Ca is also present (10 mM). Transfer to Ca-free fresh water is followed by a substantial increase in radioactive Na efflux with little or no change in the transepithelial potential. Addition of the chelating agent EDTA (2 mM) further increases Na efflux. Fis...

1. A technique has been developed for the measurement of electrical potentials (TGP's) across the gills of free-swimming, Dormitator maculatus. 2. Transfer of fish to various KCl solutions is correlated with changes in the TGP, which are not of sufficient magnitude to account for the known potassium stimulation of sodium efflux from this species. 3...

1.1. Gross turnover rates of sodium, chloride and water were measured with the use of radioisotopes. Rates were determined to be 0·28%/hr for sodium, 0·%/hr for chloride and 96%/hr for water.2.2. Calculated urine flow values indicate that despite high water permeability and supposed concomitant urine flow rates, urinary loss of chloride is only abo...

1.1. Sodium, chloride, water and urea turnover rates were measured in nurse sharks (Ginglymostoma cirratum) with the aid of radioisotopes. Results show rates of turnover to be 0·46 per cent/hr for sodium, 1·52 per cent/hr for chloride, 81 per cent/hr for water and 0·14 per cent/hr for urea.2.2. Comparison with other published data shows that while...