Gregor M Cailliet

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• Ph.D. UCSB 1972
• Professor Emeritus at Moss Landing Marine Laboratories

Owing to poorly mineralising structures, ageing deep-water elasmobranchs requires unconventional techniques. The aim of the present study was to develop an ageing method for the goblin shark Mitsukurina owstoni (Jordan, 1898) using Alcian blue staining of the vertebral column. One vertebral centrum from a male individual measuring 315.2-cm total le...

The age and growth of three endemic threatened guitarfish species were analysed using vertebrae of Pseudobatos horkelii, P. percellens and Zapteryx brevirostris. Edge and marginal‐increment analyses were used to evaluate the periodicity of the formation of the band‐pairs, suggesting deposition of one band‐pair per year, from late winter to late spr...

The Persimmon Eelpout (Eucryphycus californicus) is a relatively unknown, deep-sea fish inhabiting temperate marine waters on the west coast of North America. Using samples collected in the mid-1970s, the most recent targeted sampling for this species, we present basic life history attributes, and an analysis of the relationship between E. californ...

Age and growth estimates based on growth band counts of sectioned vertebrae have been produced for longnose skate (Raja rhina) and big skate (Beringraja binoculata [formerly Raja binoculata]) populations in the Gulf of Alaska, British Columbia and California. Previous growth studies involving estimates from different laboratories in the USA (Alaska...

The eighth in a series of workshops on fish feeding ecology (“Gutshops”) was held in 2015, continuing a tradition started in 1976 that expanded in scope and participation. Topics in early Gutshops focused on methodology and analysis, and evolved to include niche overlap, competition, nutrition, and community trophic interactions. Major accomplishme...

Garden eels occur worldwide in the tropics, but little is known about their biology and ecology. We studied Hawaiian garden eel (Gorgasia hawaiiensis) colonies near Kawaihae, Hawai'i, to investigate multiple aspects of basic biology of this species. Colonies of G. hawaiiensis occurred at depths from 16 to 36 m in soft-bottom habitat adjacent to roc...

The Aleutian skate (Bathyraja aleutica) is a large deep-water species that commonly occurs in bycatch of Alaskan trawl and longline fisheries. Although prominent in the skate biomass of the eastern Bering Sea (EBS) and Gulf of Alaska (GOA) ecosystems, minimal biological information exists. To increase our understanding of this potentially vulnerabl...

Life-history (age, growth, age validation, reproduction and demography) studies of elasmobranchs date back to the middle of the last century with major early contributions made by British fishery scientists. As predicted by Holden in the early 1970s, many sharks and rays can be vulnerable to fishery mortality because they grow slowly, mature late i...

Marine protected areas (MPAs) can potentially alter food web dynamics by increasing the density of fishes within their borders. Such increases in the density of potential competitors can cause generalist predators to contract the scope of their diets. This study investigated the effects of increased conspecific fish density on the diets of gopher r...

White sharks are highly migratory and segregate by sex, age and size. Unlike marine mammals, they neither surface to breathe nor frequent haul-out sites, hindering generation of abundance data required to estimate population size. A recent tag-recapture study used photographic identifications of white sharks at two aggregation sites to estimate abu...

Skates are prevalent in fisheries worldwide, but rarely are they identified to species. This is of conservation and management concern since skates exhibit a broad range of life history characteristics. The present study investigated the age and growth of the Starry Skate, Raja stellulata, and compared it to other regional skates inhabiting the U.S...

Vertebrae of most deep-water sharks are too poorly calcified to record visible growth bands and therefore are not useful for age determination. Most dogfish species (Order: Squaliformes) possess dorsal finspines and several recent studies have shown that these structures offer potential for age determination. Age validation should be central to any...

Although many skates possess life history characteristics that may make them vulnerable to exploitation, the detailed biological information needed to enact effective management schemes is lacking for most species. The objectives of this study were to provide age, growth, and maturity estimates for the roughtail skate, Bathyraja trachura, from the...

The sandpaper skate, Bathyraja kincaidii, is commonly taken as bycatch in trawl fisheries off central California. The impact of fisheries exploitation on this population is unknown, however little is known about its biology, including its reproductive life history. To determine reproductive aspects of B. kincaidii, 506 individuals were collected fr...

Age-structured demographic models were constructed based on empirical estimates of longevity and maturity for five deepwater Bering Sea skates to investigate how observed differences in life history parameters affect population growth rates. Monte Carlo simulations were used to incorporate parameter uncertainty. Estimated population growth rates ra...

Additional natural mortality estimates. Age-specific estimates of natural mortality (Mx) and annual survival (Sx, where Sx = ln Mx) used to parameterize demographic models in this study. Calculations follow Chen and Watanabe [41]. (DOCX)

Elasticity analysis for simulations incorporating correlation in vital rates. Predicted means and 95% confidence intervals (range bounded by 2.5th and 97.5th percentiles) of elasticities for five Bering Sea skate species. Mean values were estimated from 5,000 Monte Carlo simulations assuming perfect correlation in vital rates among age classes with...

Additional caveats and empirical needs. Additional text pertaining to the discussion section Data quality and the status of the best available science in elasmobranch demography. (DOCX)

Understanding basic life-history characteristics of white abalone (Haliotis sorenseni), such as estimated lifespan, is critical to making informed decisions regarding the recovery of this endangered species. All predictive modelling tools used to forecast the status and health of populations following restoration activities depend on a validated es...

The ability of six grenadier species from the North Atlantic, North Pacific, and Southern Ocean to sustain deep-sea fisheries is assessed. These species are captured in high amounts as bycatch and a few are taken in targeted fisheries, yet population status for most is poorly known or known for only a small portion of their range. A productivity an...

A multidisciplinary approach incorporating otolith chemistry, age data, and numerical Lagrangian particle simulations indicated a single, self-recruiting population of Antarctic toothfish (Dissostichus mawsoni) in the Southeast Pacific Basin (SPB) and Ross Sea, with a life history structured by the large-scale circulation. Chemistry deposited prior...

Characterization of fish diets from stomach content analysis commonly involves the calculation of multiple relative measures of prey quantity (%N,%W,%FO), and their combination in the standardized Index of Relative Importance (%IRI). Examining the underlying structure of dietary data matrices reveals interdependencies among diet measures, and obvia...

In this study, fishes and invertebrates collected from the continental slope (1000 m) of the eastern North Pacific Ocean were analysed using stable-isotope analysis (SIA). Resulting trophic positions (T(P) ) were compared to known diets and habitats from the literature. Dual isotope plots indicated that most species groups (invertebrates and fishes...

Results presented here provide evidence of an exception to the generalization that all chondrichthyan populations are especially vulnerable to exploitation to the extent that they remain at low abundance for a protracted or indefinite duration even after exploitation rates are reduced. Delta log-normal generalized linear models (GLM) and cluster an...

A modern synthesis of the biology of Chondrichthyans, Biology of Sharks and Their Relatives, Second Edition discusses significant advances in the development and application of new molecular techniques to the understanding of the phylogenetic relationships among and between these groups. The book considers the effect of global changes on the status...

The sandbar shark (Car-charhinus plumbeus) was the cornerstone species of western North Atlantic and Gulf of Mexico large coastal shark fisheries until 2008 when they were allocated to a research-only fishery. Despite decades of fishing on this species, important life history parameters, such as age and growth, have not been well known. Some valida...

The susceptibility of skates to fishing pressure has been well documented. In the North Atlantic, populations of two once-abundant species, the barndoor skate, Dipturus laevis, and the common skate, D. batis, may have been fished to small fractions of their historical population levels. Fishing mortality has also dramatically altered the relative a...

The sandpaper skate, Bathyraja kincaidii, is one of four skate species commonly taken in trawl fisheries off central California although very little is known about its life history. In this study, age and growth were evaluated from 187 vertebrae using a common growth band counting method. An attempt to use marginal increment analysis and centrum ed...

Information on the distribution of three species of eastern North Pacific (ENP) catsharks (Apristurus brunneus, Apristurus kampae, and Parmaturus xaniurus) and their egg cases was previously unavailable despite being a species of interest for fisheries management evaluation and policy regulation. Data were generated from specimens collected by surv...

A new species of sawshark, Pristiophorus nancyae sp. nov., is described from eight specimens collected off mozambique. The new species is the second member of the family pristiophoridae and first member of the genus Pristiophorus described from the western indian ocean. The new Pristiophorus species can be distinguished from the sympatric occurring...

Ainsley, S. M., Ebert, D. A., and Cailliet, G. M. 2011. Age, growth, and maturity of the whitebrow skate, Bathyraja minispinosa, from the eastern Bering Sea. – ICES Journal of Marine Science, 68: 1426–1434. Skates are a common bycatch in groundfish fisheries in the Bering Sea; however, their life-history characteristics are not well known. The stud...

Antarctic toothfish (Dissostichus mawsoni) are the target of an important commercial fishery in the Southern Ocean, yet age data used for management have not been comprehensively tested for accuracy. In this study, Antarctic toothfish were aged using counts of otolith growth zones based on criteria established for Patagonian toothfish, D. eleginoid...

Patagonian toothfish (Dissostichus eleginoides) or ‘Chilean sea bass’ support a valuable and controversial fishery, yet their life history is not well understood and longevity estimates range from ~20 to >50 years. In this study, lead–radium dating provided valid ages for juvenile to older adult groups, which were consistent with the counting of ot...

Skates are a common bycatch in groundfish fisheries in the Bering Sea; however, their life-history characteristics are not well known. The study is the first to investigate the age, growth, and age at maturity of Bathyraja minispinosa. Ages were estimated using sectioned vertebrae and several growth models were compared. The Gompertz model was the...

Estimates of size at maturity are crucial to fisheries stock assessments and may change spatially and temporally. This study directly compares life-history characteristics of a skate species in two large marine ecosystems in a region where there is both a directed fishery and considerable skate by-catch in other fisheries. The Bering skate, Bathyra...

The age, growth, and maturity of cabezon (Scorpaenichthys marmoratus) from California were studied from July 2000 - July 2001. Ages were estimated using otoliths (n = 641) and validated using edge analysis. Errors in age estimates were calculated using average percent error, coefficient of variation, and Index of precision. Growth was represented b...

Can there ever be a truly sustainable deep-sea fishery and if so, where and under what conditions? Ecosystem based fisheries management requires that this question be addressed such that habitat, bycatch species, and targeted fish populations are considered together within an ecosystem context. To this end, we convened the first workshop to develop...

Previous attempts to age chimaeroids have not rigorously tested assumptions of dorsal fin spine growth dynamics. Here, novel imaging and data-analysis techniques revealed that the dorsal fin spine of the spotted ratfish Hydrolagus colliei is an unreliable structure for age estimation. Variation among individuals in the relationship between spine wi...

In many regions of the world, commercial fisheries for seamount-aggregating species have collapsed. Most are trawl fisheries, which have been implicated in the destruction and loss of fragile coral and sponge habitat and potentially endemic seamount species. Even with the intense fishing effort over seamounts, our understanding of processes regulat...

The Mexican elasmobranch fishery ranks among the most important in the world, but details associated with fishing effort and species composition are generally unavailable, particularly for the extensive artisanal fishery. Seasonal surveys were conducted during 1998-1999 in the state of Baja California to determine the extent and activities of the a...

The Mexican elasmobranch fishery ranks among the most important in the world, but details associated with fishing effort and species composition are generally unavailable, particularly for the extensive artisanal fishery. Seasonal surveys were conducted during 1998–1999 in the state of Baja California to determine the extent and activities of the a...

Size at maturity, fecundity, and reproductive periodicity were estimated for the spotted ratfish, Hydrolagus colliei (Lay and Bennett, 1839), off the coast of California, Oregon, and Washington. Maximum body size and size at median maturity were greater for females than males. Skeletal muscle concentrations of the steroid hormones testosterone (T)...

We review the biology and ecology of the three known species of thresher shark (Alopiidae) occurring in the Atlantic, Pacific, and Indian Oceans: the common thresher shark (Alopias vulpinus), bigeye thresher shark (A. superciliosus), and pelagic thresher shark (A. pelagicus). We also present revised data on age, growth, and sexual maturity of the c...

Spotted sand bass, Paralabrax maculatofasciatus, were collected from Bahia de Los Angeles, Baja California, Mexico covering as wide a size range as possible over four seasons (spring, summer, fall, and winter). Age was estimated and growth parameters calculated from growth zones counted in transverse otolith sections. An otolith edge analysis indic...

Seamounts are unique and biologically productive deep-sea habitats that have often been described as having high levels of endemism, highly productive fisheries, and benthic communities vulnerable to trawl fishing. We describe the abundance and distribution of benthic megafaunal invertebrates found on 3 seamounts off central and southern California...

A large number of glass shrimp, Pasiphaea pacifica Rathburn 1902, were collected in a Tucker trawl aboard the R/V Point Sur in Monterey Bay, California during November 2006. Upon inspection, the shrimp were found to be harboring several symbionts, including a hydroid colony (Cnidaria: Hydrozoa) of unknown affinity. Shrimp-bearing hydroids were retu...

Analysis of bomb generated radiocarbon (14 C) changes in a red abalone, Haliotis rufescens Swainson shell was used to evaluate age-at-length relationships derived from data from a previous multiyear, multisite tag-recapture study. Shell carbonate was extracted from four successive growth trajectory locations in a single shell with a maximum shell l...

This study provides the first detailed information on the reproductive biology of two large and abundant eastern North Pacific Ocean skate species: big skate (Raja binoculata) and longnose skate (Raja rhina). Skates were collected in the western Gulf of Alaska during 2005 and 2006 after a targeted fishery for these two species developed around Kodi...

Apristurus brunneus, A. kampae, and Parmaturus xaniurus were caught by trawl and longline between Washington and southern California (48°N to 32°N latitude) from June 2001 through October 2004. In females, oviducal gland width increased with TL in all three species but remained within 4 to 6% of TL. Oocyte diameter increased with TL during reproduc...

Marine fisheries have spread to the deep-sea because the fishes in many of the shallow-water marine habitats have been overexploited. Many studies have found that deep-sea fishes generally grow slowly and can achieve long life spans; however, most age estimates have not been validated. Several methods for validating age and growth estimates have be...

Despite their abundance in near-shore tropical and subtropical marine environments, which support much of the world’s elasmobranch fisheries, population dynamics and impacts of fisheries on stingrays are poorly documented. Age-structured demographic models were developed using empirical estimates of fecundity, longevity and maturity to project popu...

We provide a detailed description of growth zone counts at two locations in the skeletal structure of four bamboo coral colonies (Family Isididae, sub-family Keratoisidinae, genera Lepidisis spp. and Keratoisis sp. from New Zealand). Zone counts were made microscopically on skeletal cross-sections of calcareous internodes producing counts of up to...

This study provides the first published age estimates for the roughtail skate, Bathyraja trachura. Age and growth characteristics of B. trachura, a poorly-known deepwater species, were determined from samples collected along the continental slope of the contiguous western United States. A new maximum size was established at 91.0cm TL. Age was deter...

Feeding studies can provide researchers with important insights towards understanding potential fishery impacts on marine systems. Raja rhina is one of the most common elasmobranch species landed in central and northern California demersal fisheries, yet life history information is extremely limited for this species and aspects of its diet are unkn...

The stomachs of 130 sandpaper skates, Bathyraja kincaidii (Garman, 1908), were sampled from off central California to determine their diet composition. The overall diet was dominated by euphausiids, but shrimps, polychaetes and squids were also important secondary prey. A three-factor MANOVA demonstrated significant differences in the diet by sex,...

Age and growth estimates for the shortfin mako, Isurus oxyrinchus, derived from vertebral centra of 258 specimens (118 males, 140 females), ranging in size from 64 to 340 cm fork length (FL) were compared with data from 22 tag–recaptured individuals (74–193 cm FL) and length–frequency data from 1822 individuals (1035 males, 787 females; 65–215 cm F...

Validated age and growth estimates are important for constructing age-structured population dynamic models of chondrichthyan fishes, especially those which are exploited. We review age and growth studies of chondrichthyan fishes, using 28 recent studies to identify areas where improvements can be made in describing the characteristics of ageing str...

Age estimation is an issue for the shortfin mako, Isurus oxyrinchus, because of disagreement on vertebral band-pair deposition periodicity. In the 1950s–1960s, thermonuclear testing released large amounts of radiocarbon into the atmosphere, which diffused into the ocean through gas exchange. This influx created a time-specific marker that can be us...

The genus Apristurus has been divided formerly into three species subgroups based on morphological and molecular phylogenies. Previous studies have agreed on the separation into distinct species groups, the largest two of which have been described as the brunneus and spongiceps groups. An examination of the egg cases produced by these oviparous cat...

Esta investigación fue posible realizarla en gran parte a través de los fondos proporcionados por la FUNDACIÓN

Canary rockfish (Sebastes pinniger) have long been an important part of recreational and commercial rockfish fishing from south-east Alaska to southern California, but localised stock abundances have declined considerably. Based on age estimates from otoliths and other structures, lifespan estimates vary from ~20 years to over 80 years. For the pur...

Maturity and growth characteristics were estimated for Dasyatis dipterura from western Mexico, where it is a common component of artisanal elasmobranch fisheries. Median disc width at maturity was estimated as 57.3 cm for females (n = 126) and 46.5 cm for males (n = 55) respectively. Age estimates were obtained from 304 fishery-derived specimens (1...

There is an ongoing disagreement regarding the aging of the shortfin mako due to a difference of interpretation in the periodic deposition of vertebral growth band pairs, especially for the larger size classes. Using analysis of length-month information, tagging data, and length-frequency analysis, concluded that two band pairs were formed in the v...

Long-term trends in the elasmobranch assemblage of Elkhorn Slough, Monterey Bay, California, were analyzed by documenting species composition and catch per unit effort (CPUE) from 55 sport fishing derbies that occurred during May, June, and July, from 1951 until 1995. The most abundant species (bat ray, Myliobatis californica; shovelnose guitarfish...

Validated age and growth estimates are important for constructing age-structured population dynamic models of chondrichthyan fishes, especially those which are exploited. We review age and growth studies of chondrichthyan fishes, using 28 recent studies to identify areas where improvements can be made in describing the characteristics of ageing str...

The white shark, Carcharodon carcharias, has a complex life history that is characterized by large scale movements and a highly variable diet. Estimates of age and growth for the white shark from the eastern North Pacific Ocean indicate they have a slow growth rate and a relatively high longevity. Age, growth, and longevity estimates useful for sto...

The bank rockfish, Sebastes rufus, is part of a deep-water (31–454 m) rockfish community that is fished commercially off California and has experienced population decline. This species is considered very difficult to age with traditional methods of counting growth increments in otolith cross-sections, creating the need to confirm age estimates with...