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Estimates of animal abundance are widely used to support conservation and resource management. For populations in open systems, abundance estimates from tagging data can be highly uncertain or biased. Here, we develop a novel approach to estimate abundance of an open population by pairing two models, each utilizing distinct tagging data. Using data from telemetry tags, we infer movement rates to and from the study site with a Markovian model allowing for an environmental effect. Then, using data from conventional passive tags, we apply a Lincoln–Petersen abundance estimator modified to account for mortality and movement. After developing the model within a Bayesian framework, we demonstrate its application to data on gray triggerfish (Balistes capriscus) tagged in the Atlantic Ocean off North Carolina, USA. For this open population, we estimate site abundance to be ∼1000 fish (∼2000 fish·km–2) and additionally find evidence for an effect of hurricanes on movement. The general approach may be useful for fisheries, wildlife, and other ecological studies utilizing multiple tag types, particularly for estimating abundance of an open population.

Balistes polylepis Steindachner, 1876. Finescale Triggerfish. To 80 cm (31.5 in) TL (De La Cruz-Ag��ero et al. 1997). Metlakatla, south-eastern Alaska (Karinen et al. 1985; see comment under Melichthys niger below) to San Antonio (about 33��32���S), central Chile (Brito 2003), including Gulf of California (Bussing in Fischer et al. 1995), Islas Gal��pagos (Grove and Lavenberg 1997), and Hawai���i (Randall and Mundy 1998). Only one Alaska record and isolated records from Washington to California; most common south of California (Mecklenburg et al. 2002). Benthic; depth: 2���512 m (6���1,680 ft) (min.: Personal communication: Scripps Institution of Oceanography Fish Collection, La Jolla, California; max.: Miller and Lea 1972)., Published as part of Love, Milton S., Bizzarro, Joseph J., Cornthwaite, Maria, Frable, Benjamin W. & Maslenikov, Katherine P., 2021, Checklist of marine and estuarine fishes from the Alaska-Yukon Border, Beaufort Sea, to Cabo San Lucas, Mexico, pp. 1-285 in Zootaxa 5053 (1) on page 223, DOI: 10.11646/zootaxa.5053.1.1, http://zenodo.org/record/5578008, {"references":["De La Cruz-Aguero, J., Martinez, M. A., Cota-Gomez, V. M. & De La Cruz-Aguero, G. (1997) Catalogo de los Peces Marinos de Baja California Sur. Centro Interdiscipinario de Ciencias Marinas.","Karinen, J. F., Wing, B. L. & Straty, R. R. (1985) Records and sightings of fish and invertebrates in the eastern Gulf of Alaska and oceanic phenonmenon related to the 1983 El Nino event. In: Wooster, W. S. & Fluherty, D. L. (Eds.), El Nino North: Nino Effects in the Eastern Subarctic Pacific Ocean. Washington Sea Grant Program, University of Washington, Seattle.","Brito, J. L. (2003) Nuevos registros de Balistes polylepis (Balistidae), Sphoeroides lobatus (Tetraodontidae), Mola mola y M. ramsayi (Molidae) en San Antonio, Chile (Pisces, Tetraodontiformes). Investigaciones Marinas, Valparaiso, 31, 77 - 83.","Fischer, W., Krupp, F., Schneider, W., Sommer, C., Carpenter, K. E. & Niem, V. H. (1995) Guia FAO para la identificacion para los fines de la pesca. Pacifico centro-oriental. Volume II, Vertebrados, Parte 1. Volume III, Vertebrados, Parte 2. FAO, Rome.","Grove, J. S. & Lavenberg, R. J. (1997) The Fishes of the Galapagos Islands. Stanford University Press, Stanford.","Randall, J. & Mundy, B. C. (1998) Balistes polylepis and Xanthichthys caeruleolineatus, two large triggerfishes (Tetraodontiformes: Balistidae) from the Hawaiian Islands, with a key to Hawaiian species. Pacific Science, 52, 322 - 333.","Miller, D. J. & Lea, R. N. (1972) Guide to the coastal marine fishes of California. California Department of Fish and Game Fish Bulletin, 157."]}

The overexploitation of many traditionally targeted reef fishes, such as red snapper, Lutjanus campechanus (Poey, 1860), alongside the implementation of increasingly restrictive management measures on those species, has led to increased targeting of conventionally discarded Gulf of Mexico gray triggerfish, Balistes capriscus Gmelin, 1789, commercially and recreationally. The goal of this study was to assess age and growth of gray triggerfish from the Alabama Artificial Reef Zone in the north-central Gulf of Mexico. Gray triggerfish (n = 1135) were collected predominantly from artificial habitat during 1999–2017. Specimens were sexed macroscopically and ages were assigned by counting translucent increments in sections of the first dorsal spine. Fish ranged in size from 22 to 617 mm fork length. The oldest female was assigned an age of 9 yrs; the oldest male, 10 yrs. A suite of growth models was tested to develop combined and sex-specific models. The von Bertalanffy growth function best fit the combined data with parameters L∞ = 488.63 (SE 5.19), k = 0.57 (SE 0.02), and t 0= –0.27 (SE 0.03). Mean size-at-age differed between sexes for six of the eight ages which possessed sample sizes large enough to make comparisons. Growth differed between sexes, and the best-fitting version of the von Bertalanffy growth function permitted L∞ to vary by sex [female L∞ = 480.26 (SE 7.99); male L∞ = 532.89 (SE 8.95); k = 0.44 (SE 0.04); t 0 = –0.78 (SE 0.16)]. These findings enhance our knowledge of the age and growth of Gulf of Mexico gray

Fossils of Balistes are reported for the first time from Miocene deposits in Cuba including the description of a new taxon, † Balistes vegai sp. nov., and the first record of † B. crassidens on the island. At the same time several taxonomic and nomenclatural issues regarding other fossil specimens are assessed, including the reassignment of some incorrect records of Balistes and the recognition of † B. dubius as valid name. A table of dental characters and character states is provided to facilitate future identification of fossil species of Balistes. The fossil record of triggerfish indicate that crown Balistes evolved at least during the Oligocene, and that by the Miocene was occupying in the Atlantic, similar niches to those exploited by modern taxa.

Seafood products are perceived as healthy foods. However, several species of seafood are still not fully utilized for different reasons or can be valued outside the original locale, if issues with the short shelf-life and/or the preparation/presentation form are overcome, e.g., gray triggerfish, Balistes capriscus. Consumed mostly fresh, its flesh is of excellent quality. We studied the effect of different types of packaging (in air (AIR), vacuum (VP), and modified atmosphere (MAP)) on physicochemical (color and texture, pH, and total volatile basic nitrogen), microbiological (total viable count, psychrotrophic, sulphide-reducing bacteria, and acid-lactic bacteria), and sensory qualities, and shelf-life of gray triggerfish fillets stored at refrigeration temperature for 15 days. The samples were analyzed on days 0 (fresh fish), 5, 10 (8 and 12 for sensory analysis), and 15 after filleting and packaging. During the trial, fillets became lighter (increased L*) and yellower (b* &gt, &gt, 0) with time of storage. Distinct patterns were observed for pH among treatments. Unexpectedly, the increasing trend observed in the texturometer-derived hardness of VP and MAP fillets, contrasted with the sensory assessment, wherein panelists perceived a clear softening of fillets. VP delayed and MAP inhibited the increase in TVB-N contents of fillets compared to fillets packed in AIR. Total viable count and psychrothropic bacteria of fillets in AIR exceeded the conventional limit of 7 log(CFU/g) on day 10, while in fillets packed in VP and MAP, their abundance remained below that limit during the trial. The organoleptic attributes of fillets perceived by a sensory panel changed significantly in all treatments during the storage trial. Willingness to consume the fillets decreased constantly in AIR and MAP, but not in VP fillets. Considering primarily sensory, but also biochemical and microbiological parameters, namely panelists&rsquo, rejection, total volatile basic nitrogen content, and total viable count and psychrotrophic bacteria abundance, the shelf-life of fillets packed in air was eight days. Vacuum and modified atmosphere packaging extended the shelf-life to 15 and 12 days, and thus can add value to this product. Future research regarding the VP and MAP of gray triggerfish fillets could involve the optimization of mixtures of gases use and/or the application of combined processes.

In the Gulf of California, mineral deposits have contributed to high metal contents in coastal environments. This study examined cadmium, lead, copper, zinc, and iron contents in three fish species, Kyphosus vaigiensis (herbivore), Stegastes rectifraenum (omnivore), and Balistes polylepis (carnivore) at two mining sites. Metal concentrations were analyzed by atomic absorption spectrophotometry and stable nitrogen and carbon isotopes were estimated using mass spectrophotometry. Also, we assessed the risk to human health from the consumption of these three species based on permissible limits, although only two of them (Kyphosus and Balistes) are consumed as food. Metal concentrations differed among fish species, except for iron. The highest concentrations of metals were not always recorded in the species at the highest trophic level, i.e., Balistes. The highest concentrations (dry weight) recorded were cadmium (0.21 &plusmn, 0.03 &micro, g g&minus, 1) and lead (1.67 &plusmn, 0.26 &micro, 1), in S. rectifraenum, copper (1.60 &plusmn, 0.49 &micro, 1) and zinc (67.30 &plusmn, 8.79 &micro, 1), in B. polylepis, and iron (27.06 &plusmn, 2.58 &micro, 1), in K. vaigiensis. Our findings show that each element accumulates differently in particular marine organisms, depending on the physiology of the species and the biogeochemistry of its habitat, which in turn is affected by the anthropogenic activities in adjacent areas. No risk of heavy metals toxicity is expected from the human consumption of the species and sites studied

Anthropogenic factors that negatively impact reef fishes can include changes in life-history patterns of fisheries-targeted species. Understanding these impacts on growth and population age structure is essential in the management of exploited populations of fishes. This is the first study to directly compare age and growth for a major fisheries species between east and west populations of a transatlantic reef fish. The main goal of this study was to document age and growth in grey triggerfish Balistes capriscus from coastal waters of Ghana in the Gulf of Guinea (GOG) and compare those with the previous growth studies from that region and with the western Atlantic population. A secondary objective of this study was to evaluate the use of otoliths to age triggerfish and to provide a preliminary comparison with spine-derived age estimates. The results obtained from this study provided an updated understanding of the growth and age structure of the eastern B. capriscus population in GOG. The authors documented that shifts in population attributes occurred for B. capriscus after its major decline in abundance. The differences in physical and biotic characteristics of the East and West Atlantic regions and the differences in collection methods of samples make direct comparisons of growth parameters difficult. Nonetheless, overall differences in maximum sizes and ages were apparent; the western Atlantic population had a larger maximum size and older maximum age. The authors also documented that sagittal otoliths can be used to provide age estimates for triggerfish species, and otoliths as an ageing structure had better between-reader precision compared to dorsal spines.

Three digeneans belonging to the Opecoelidae are reported and described from triggerfishes (Tetraodontiformes: Balistidae) collected in the northern Red Sea off Egypt. Both Macvicaria longicirrata (Manter, 1963) Aken-Ova, Cribb & Bray, 2008 and Neopycnadena tendu (Bray & Justine, 2007) n. comb. were recovered from the intestine of the titan triggerfish, Balistoides viridescens (Bloch & Schneider)—each represents a new host record—and Gaevskajatrema balistes n. sp. was found parasitizing the lower intestine of the Picasso triggerfish, Rhinecanthus assasi (Forsskål). We continue to support synonymy of Gaevskajatrema ponticum (Koval, 1966) Machkevsky, 1990 with Gaevskajatrema perezi (Mathias, 1926) Gibson & Bray, 1982, not as a differentiated species. We adopt the restricted posterior extension of the ceca and vitellarium to the testicular zone, without extension of either into the post-testicular space, as diagnostic in distinguishing Gaevskajatrema. Gaevskajatrema balistes n. sp. differs from G. perezi based on its substantially smaller body size with fewer eggs, a longer cirrus-pouch reaching ovarian level and it parasitizes a distinct host group from a structurally and ecologically different ecosystem. Neopycnadena n. gen. is erected for Pseudopycnadena tendu Bray & Justine 2007 based on its possessing a large broadly oval cirrus-pouch with a massive field of prostatic cells occupying the entire volume of the cirrus-pouch, a wide, cup-shaped and thick-walled ejaculatory duct, distinct dorsal position of the excretory pore, the bifurcal dextral position of the genital pore, its report from a distinct host group and distant locality and its phylogenetic uniqueness compared with Pseudopycnadena fischthali Saad-Fares & Maillard 1986. Neopycnadena n. gen. is ecologically similar to opistholebetines in their life-cycles and morphology; however, phylogenetically separate from opistholebetines as well as from the Polypipapiliotrematinae Martin, Cutmore & Cribb in Martin, Sasal, Cutmore, Ward, Aeby & Cribb, 2018 and members of Clade [C] of Martin and colleagues, thus we conclude that Neopycnadena n. gen. is unique. Neopycnadeninae n. subfam. is proposed to accommodate Neopycnadena n. gen. We consider that the probable characterization of tetraodontiform specialist taxa (as indicated by the presence of a muscular post-oral ring) and the specificity of the Opistholebetinae Fukui, 1929 sensu stricto with a tetraodontiform host are no longer reliable characters differentiating Gaevskajatrema and Macvicaria Gibson & Bray, 1982. The nature of the post-oral structure is discussed and it is adopted to be a diagnostic feature at the generic level among taxa of the Opistholebetinae sensu latu. It is concluded that the expanded concept of the Opistholebetinae is more supported than the restricted one, Birendralebes Srivastava & Ghosh, 1972 remains incertae sedis within the Opecoelidae Ozaki, 1925 rather than in the Opistholebetinae, and we provide a generic key to the Opistholebetinae.

Balistes capriscus Gmelin 1789 ���Grey triggerfish Taxonomy. First record from Lebanon as Balistes capriscus Linnaeus 1758 by George et al. (1964: 24); subsequently recorded as Balistes carolinensis Gmelin by Mouneimn�� (1977: 66); as Balistes carolinensis Gmelin 1789 by Mouneimn�� (2002: 242���243); recently recorded as Balistes carolinensis by Harmelin-Vivien et al. (2005: 629). Material in collection: AUBM and USNM. Distribution. Mediterranean Sea, Sea of Marmara, Black Sea, Atlantic Ocean. Conservation. IUCN: Global (VU: A2bd, 6 June 2011); Med. (NE). Capture and threats: FIT, unknown. Occurrence: Common. Low priority for conservation action., Published as part of Bariche, Michel & Fricke, Ronald, 2020, The marine ichthyofauna of Lebanon: an annotated checklist, history, biogeography, and conservation status, pp. 1-157 in Zootaxa 4775 (1) on page 113, DOI: 10.11646/zootaxa.4775.1.1, http://zenodo.org/record/3983887, {"references":["George, C. J., Athanassiou, V. A. & Boulos, I. (1964) The fishes of the coastal waters of Lebanon. Miscellaneous Papers in the Natural Sciences. The American University of Beirut, 4, 1 - 24.","Mouneimne, N. (1977) Liste des poissons de la cote du Liban (Mediterranee orientale). Cybium, 3 (1), 37 - 66.","Mouneimne, N. (2002) Poissons marins du Liban et de la Mediterranee orientale. INCAM-EU / CNRS Lebanon, Beyrouth, 271 pp.","Harmelin-Vivien, M. L., Bitar, G., Harmelin, J. G. & Monestiez, P. (2005) The littoral fish community of the Lebanese rocky coast (eastern Mediterranean Sea) with emphasis on Red Sea immigrants. Biological Invasions, 7, 625 - 637. https: // doi. org / 10.1007 / s 10530 - 004 - 5852 - 4"]}

Field removal and laboratory studies examined competitive interactions between gray triggerfish (Balistes capriscus) and red snapper (Lutjanus campechanus). In field studies, all gray triggerfish and red snapper were counted and sizes estimated on 24 reef sites. Gray triggerfish were then removed from half of these reef sites, resulting in significantly fewer gray triggerfish on the removal reefs at the start of the experiment. After 7 months the experiment ended and reef sites were resurveyed. Gray triggerfish decreased on both treatments, while the mean number of red snapper did not differ between treatments; however, there were significantly more small (

Ciguatera fish poisoning is a seafood-toxin illness resulting from consumption of fish contaminated with ciguatoxins. Managing ciguatera fish poisoning is complex. It is made easier, however, by local fishers from endemic areas reporting regional predictability for local fish species' ciguatera fish poisoning risk, which the present study then tested. We investigated the prevalence of ciguatoxins in 4 commonly marketed and consumed species (Balistes vetula, Haemulon plumierii, Ocyurus chrysurus, and Epinephelus guttatus) across an oceanic gradient (north, south, east, and west) from the US Virgin Islands. Fish muscle extracts were analyzed for Caribbean ciguatoxins using an in vitro mouse neuroblastoma (N2a) cytotoxicity assay and confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Fish collected from the north location had 0 fish with detectable ciguatoxins; this site also had the greatest wave energy. Caribbean ciguatoxins in fish ranged from 0.01 to 0.11, 0.004 to 0.10, and 0.005 to 0.18 ng Caribbean ciguatoxin-1 eq/g, from the west, east, and south respectively. Ciguatoxin-like activity was detectable by the N2a assay in 40, 41, 50, and 70% of H. plumierii, O. chrysurus, B. vetula, and E. guttatus, respectively. Of the fish collected, 4% had Caribbean ciguatoxin levels exceeding the US Food and Drug Administration guidance of 0.1 ng Caribbean ciguatoxin-1 eq/g fish. These findings concurred with spatial ciguatera fish poisoning prevalence information provided by local fishers in the US Virgin Islands and demonstrate how partnerships between researchers and fishers can aid the improvement of science-based ciguatera fish poisoning management. Environ Toxicol Chem 2018;39:1852-1863. Published 2018 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

The demersal fish are a commercial resource of small-scale fisheries of northern Colombian Caribbean. Balistes capriscus is frequently and important in fishing landings, but this species has not economic value and its trophic ecology is unknown. Due to this, the diet was examined using the stomach contents and stable isotopes analysis. The individuals were collected with fish pots during two seasonal research expeditions in May and August of 2018. The δN and δC values were significantly different between size classes, indicating ontogenetic shifts in habitat use and consumption of prey. The δC shows that the triggerfish tends to feed in areas closer to the coast and his source of its origin can possibly change from the pelagic zone when they are juveniles, to the benthic trophic networks in his adulthood. The trophic position mean according to Bayesian inferences and Post's estimates was 2.98 and 3.03 and increased with size. Likewise, isotopic niche width corroborates the ontogenetic shift related with the maturity groups., This study is framed in the research project “Marine environmental productivity and quality of the northern Colombian Caribbean as an axis for the regional development of the departments of La Guajira and Magdalena: analysis from the coupling of the atmospheric, oceanographic and biological components” executed by the research group DIMARCO (Jorge Tadeo Lozano University). This study was supported by the Magdalena and La Guajira governorates and operated and supervised by COLCIENCIAS (Code: 120274859287, CT-075-2017).

Growth zones in dorsal spines of grey triggerfish Balistes capriscus from the northern Gulf of Mexico were utilized to estimate growth and examine factors that may affect estimates of size at age. Age was estimated from dorsal-spine sections of 4687 individuals sampled from U.S. waters during 2003-2013, including both fishery-independent (n = 1312) and fishery-dependent (n = 3375) samples. Ninety-six per cent (n = 4498) of these sections were deemed suitable for ageing; average per cent error between two independent readers was 10·8%. Fork length (LF ) ranged from 65 to 697 mm and age estimates from 0 to 14 years. Both sex and sample source (fishery-independent v. recreational) significantly affected estimated size at age for 2-6 year-old fish. Data were pooled between sources to fit sex-specific von Bertalanffy growth functions. Results for the female model were L∞ = 387 mm LF , k = 0·52 year-1 and t0 = 0·01 year, while for males L∞ = 405 mm LF , k = 0·55 year-1 and t0 = 0·02 year. These results were significantly different between sexes and indicate clear sexual dimorphism. Thus, growth should be modelled separately by sex when examining population parameters or conducting stock assessment modelling. The positive bias in estimates of size at age computed for recreational v. fishery-independent samples also has clear implications for stock assessment as growth functions computed with fishery-dependent samples would tend to overestimate stock productivity.

The levels of toxic heavy metals (Al, Cd, Pb), macroelements (Ca, K, Mg, Na) and microelements and trace elements (B, Ba, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Sr, V, Zn) were determined in 54 muscle samples from three species of fish for human consumption, Balistes capriscus (grey triggerfish), Canthidermis sufflamen (oceanic triggerfish) and Heteropriacanthus fulgens (rock catalufa), using spectrometry of inductively coupled plasma optical emission (ICP-OES). The aims of this study is to determine if the three species are good bioindicators of environmental pollution and to verify whether they are suitable for human consumption. Significant differences were found in the levels of Al, B, Fe, K, Mn, Mo, Na and Zn between the three species studied. The results suggest that the underwater volcano off El Hierro influences the metallic content (Al, K the most characteristic) of H. fulgens. An evaluation of the toxic risk derived from the ingestion of B. capriscus, C. sufflamen and H. fulgens was carried out, analyzing the Admissible Daily Intake (ADI) and the Safety Margin (MoS). For the nutritional study, the Recommended Daily Intake (RDI) index was used. Therefore, once the study has been carried out and under the conditions established in terms of daily / weekly fish consumption, proposed by AESAN, there would not be any type of toxic risk after ingesting B. capriscus, C. sufflamen and H. cruentatus.

The Gray Triggerfish Balistes capriscus supports fisheries on both sides of the Atlantic Ocean. We utilized fishery-independent samples to assess the age structure, growth, sex ratio, size and age at maturity, spawning season, and spawning frequency of the Gray Triggerfish population off the southeastern U.S. Atlantic coast. From 1991 to 2012, 7,685 samples were collected, ranging in FL from 82 to 578 mm and ranging in age from 0 to 13 years. Our study provides key life history information for an exploited population and is the first to comprehensively describe age, growth, and reproduction for a Balistes species. We documented that the Gray Triggerfish is sexually dimorphic, with adult males attaining larger sizes at age and a larger maximum size than females. Sex-specific growth curves were fitted, yielding the following von Bertalanffy equations: FLt = 419[1 – e–0.54(t + 0.61)] for males and FLt = 352[1 – e–0.94(t + 0.22)] for females. This species is characterized by a medium size at maturity ...

Artificial reefs are commonly created with the goal of enhancing fish populations. However, many studies evaluating their effects on these populations have been hindered by a lack of preconstruction data from existing natural habitats and temporal comparisons with control areas. Here, we present findings from a before–after control–impact study designed to assess the effects of a new artificial reef on fish populations in the western Gulf of Mexico. Vertical line and fish traps were used to sample the reef site and a paired control site with soft bottom substrates for 1 year before and 2 years after reef construction. Prior to reef construction in October 2013, and over bare substrates in general, infrequent catches of sea catfishes and small coastal sharks were observed. With the exception of rare occurrences of juvenile Gray Triggerfish Balistes capriscus and Red Snapper Lutjanus campechanus, which were observed only during the summer recruitment season, the control site exhibited a lack of reef...

This work was supported by the Marine Fisheries Initiative program of the U.S. National Marine Fisheries Service. Movement is a central feature of the ecology of fish, yet the study of fish movement has been inhibited due to its multidimensional nature and technological and analytical limitations. We used a relatively new fine-scale acoustic tracking system to quantify movements of an economically valuable, demersal marine fish species (gray triggerfish Balistes capriscus) on a natural hardbottom reef on the continental shelf of North Carolina, USA. Overall, 30 fish were tagged and released, and 104,170 highly precise (-1–3 m) spatial positions were estimated during the 43-d study. To quantify gray triggerfish movements, we used a combination of exploratory data analyses and hidden Markov models (HMM), the latter of which can identify and elucidate normally hidden behavioral states. Both methods suggested gray triggerfish movements varied by diel period and among individuals, and that some of the variation among individuals could be explained by fish size. Depending on model specification, HMMs identified two or three behavioral states, one of which was likely resting that occurred mostly at night and another was likely foraging or transit that occurred mostly during the day. Moreover, resting at night occurred in small, discrete patches within the study area, whereas foraging or transit behaviors occurred broadly throughout the study area. We encourage a wider use of acoustic telemetry and HMMs to shed light on the normally hidden behaviors of demersal fishes. Postprint

Little is known about the movement patterns of gray triggerfish, Balistes capriscus Gmelin, in the northern Gulf of Mexico. To examine fine-scale movements, gray triggerfish (n = 17) were tagged with transmitters and tracked with the VR2W Positioning System from 17 October 2012 to 9 December 2013. Most (76%) tagged fish survived and were tracked for 1–57 weeks. Tagged fish showed significantly larger home ranges and core areas in autumn than winter–spring and during day than night. Seasonal movement patterns were positively correlated with water temperature. Gray triggerfish stayed close to the reef (mean ± SD distance = 35.9 ± 28.4 m) and showed high site fidelity (64%) and high residency (>57 weeks). These patterns emphasise the importance of structured habitat for this species and suggest that artificial reef building in the northern Gulf of Mexico has enhanced this population.

This study tested the potential for 27 artificial reefs, which were deployed in the northeastern Gulf of Mexico (nGOM) but not reported to the public, to serve as refuges from fishing mortality for reef fishes. Red Snapper Lutjanus campechanus (n = 2,114) and Gray Triggerfish Balistes capriscus (n = 267) were tagged at a subset (n = 9) of the study reefs from winter 2005 to fall 2007 to estimate their site fidelity and mortality rates. Mortality was also estimated from catch curves fit to Red Snapper and Gray Triggerfish age distributions that were estimated at the study reefs both before (2005–2007) and after (2007–2008) the GPS coordinates of the above subset were advertised to the public. Red Snapper site fidelity (f), estimated by fitting Burnham's (1993) joint encounter model to tagging data, was 12.8% per year; while estimated instantaneous total mortality (Z) of Red Snapper ranged from 0.08 per year during the closed recreational fishing seasons to 1.31 per year during the open seasons. Sim...

Single specimens of Finescale Triggerfish (Balistes polylepis) and Louvar (Luvarus imperialis) were found in British Columbia’s coastal waters in 2014. Both B. polylepis and L. imperialis normally are found off southern-most California and Baja California. Although a stray B. polylepis was caught as far north as Metlakatla, Alaska, during the 1982–1983 El Nino event, and L. imperialis is known to stray north along the Washington coastline, these 2 new specimens represent 1st records for British Columbia. Both probably moved north during the warm-water anomaly that has persisted along the North American coast since 2013.

This study evaluates the habitat characteristics, fishing effort, and production, as well as changes in the individuals, such as changes in size frequency, of the spawning aggregations of mutton snapper Lutjanus analis and grey triggerfish Balistes capriscus, caught in the Chinchorro Bank Biosphere Reserve (CBBR), Mexico. The mutton snapper aggregation was located in coral patches, while the spawning aggregation of grey triggerfish was located on the windward terrace of the reef flat. Fishery data was obtained for the duration of the spawning event in 2008, with a total of 5 days for mutton snapper and 4 days for grey triggerfish. The fishery recorded a total of 830 mutton snappers, with individual sizes ranging from 40 to 77 cm in fork length (FL). Individual size and catch per unit effort (CPUE) decreased through time, with the lowest values presented at the end of the 5 days. In contrast, a total of 665 grey triggerfish were recorded in the catch, ranging from 45 to 61 cm (FL) with the largest sizes caught at the end of the fishing period, concurrently with the lowest CPUE. A lack of governance allowed both species to be harvested during their spawning aggregations. The creation of an international body composed of fishers, managers, conservationists, and scientists from the countries belonging to the Mesoamerican Reef System is urgently required to look for agreements in conservation and management strategies of these commercially important species.

We estimated condition-specific survival rates of gray triggerfish (Balistes capriscus) using a tag-recapture approach and extrapolated these values to produce an overall discard survival estimate for the US South Atlantic recreational hook-and-line fishery. Tag return rates of fish tagged at the seafloor using SCUBA served as a reference for return rates of fish tagged at the surface. We examined the validity of gross necropsy as a proxy for survival by identifying likely causes of discard mortality. Best-condition surface-released fish (no external trauma) had an estimated mean proportional survival of 0.39 (95% confidence interval 0.28, 0.55). For gray triggerfish exhibiting visible trauma, estimated survival was 0.24 (0.10, 0.60). Floating fish had a survival rate of zero. The necropsy-based estimate of gray triggerfish lacking organ displacement closely matched the tag-based estimate of survival. Mean estimated discard survival across all depths for North Carolina was 0.35 (0.10, 0.59) and for Florida was 0.34 (0.08, 0.59). These results have implications for gray triggerfish management because our estimate of discard survival is substantially lower than previously assumed and for future discard survival research given our findings with gross necropsies.

Tetraodontiform fishes are characterized by jaws specialized for powerful biting and a diet dominated by hard-shelled prey. Strong biting by the oral jaws is an unusual feature among teleosts. We present a functional morphological analysis of the feeding mechanism of a representative tetraodontiform, Balistes vetula. As is typical for the order, long, sharp, strong teeth are mounted on the short, robust jaw bones of B. vetula. The neurocranium and suspensorium are enlarged and strengthened to serve as sites of attachment for the greatly hypertrophied adductor mandibulae muscles. Electromyographic recordings made from 11 cranial muscles during feeding revealed four distinct behaviors in the feeding repertoire of B. vetula. Suction is used effectively to capture soft prey and is associated with a motor pattern similar to that reported for many other teleosts. However, when feeding on hard prey, B. vetula directly bit the prey, exhibiting a motor pattern very different from that of suction feeding. During buccal manipulation, repeated cycles of jaw opening and closing (biting) were coupled with rapid movement of the prey in and out of the mouth. Muscle activity during buccal manipulation was similar to that seen during bite-captures. A blowing behavior was periodically employed during prey handling, as prey were forcefully "spit out" from the mouth, either to reposition them or to separate unwanted material from flesh. The motor pattern used during blowing was distinct from similar behaviors described for other fishes, indicating that this behaviors may be unique to tetraodontiforms. Thus B. vetula combines primitive behaviors and motor patterns (suction feeding and buccal manipulation) with specialized morphology (strong teeth, robust jaws, and hypertrophied adductor muscles) and a novel behavior (blowing) to exploit armored prey such as sea urchins molluscs, and crabs. © 1993 Wiley-Liss, Inc.

The localization of intestinal glycoconjugates of the blunthead pufferfish Sphoeroides pachygaster and the grey triggerfish Balistes capriscus from the north-western Ionian Sea was analysed by histochemical methods (PAS, AB pH 2.5, HID) and lectin binding experiments (WGA, LFA, SBA, sialidase-SBA, PNA, sialidase-PNA, ConA, AAA, UEA-I, LTA) to assess how evolutionary loss of a functional stomach in S. pachygaster affects intestinal secretions relative to the B. capriscus, which retains the plesiomorphic gastric condition. Sphoeroides pachygaster had a lower content of acid mucins but more complex sialylation patterns than B. capriscus. GalNAc and GlcNAc residuals were present in both, but GalNAc residuals in S. pachygaster were subterminal to sialic acid. Balistes capriscus lacked galactosylated residuals and its enterocytes had a glycocalyx that differed in composition between the small intestine and the rectum and was missing from S. pachygaster. Functional and ecological implications of these findings are discussed.

The feeding ecology of two reef fishes associated with artificial reefs in the northwest Gulf of Mexico (GoM) was examined using gut contents and natural stable isotopes. Reefs were divided into three regions (east, central, west) across an east to west gradient of increasing reef complexity and salinity. Gray triggerfish (Balistes capriscus) primarily consumed reef-associated prey (xanthid crabs, bivalves, barnacles) and pelagic gastropods, while red snapper (Lutjanus campechanus) diets were mainly comprised of non-reef prey (stomatopods, fishes, portunid crabs). Natural stable isotopes of carbon (δ13C), nitrogen (δ15N), and sulfur (δ34S) were measured in consumer muscle tissue as well as potential primary producers. Gray triggerfish occupied a lower trophic position than red snapper, with lower δ13C and δ15N values across all size classes and regions, and generally higher δ34S values. Red snapper had a smaller range of stable isotope values and corrected standard ellipse areas across all size classes and regions, indicating a smaller isotopic niche. Contribution estimates of particulate organic matter (26 to 54%) and benthic microalgae (BMA, 47 to 74%) for both species were similar, with BMA contributions greater across all three size classes (juveniles, sub-adults, adults) of red snapper and all but the juvenile size class for gray triggerfish. Species gut contents and stable isotopes differed by region, with fishes consuming more crabs in the east region and more gastropods in the central and west regions. δ13C and δ15N values generally decreased from east to west, while δ34S increased across this gradient. Results highlight species-specific feeding differences associated with artificial reefs, where gray triggerfish may be more dependent on the reef structure for foraging opportunities. In addition, results offer further information on the integral role of BMA in primary production at nearshore artificial reefs.

Adults of both sexes of Naobranchia variabilis Brian, 1924 (Lernaeopodidae) are described based on material collected from the gill filaments of Balistes capriscus Gmelin, caught off the coast of Algeria. This is the second species of Naobranchia Hesse, 1863 to be found in the Mediterranean and the host record is new. Morphological comparisons are made with existing descriptions of N. variabilis and it is inferred, from small variations between material from different hosts and different localities, that N. variabilis may represent a species complex. The corrugated lobes on the head of Naobranchia females are interpreted as novel structures involved with temporary attachment during feeding.

The age and growth parameters of grey triggerfish, Balistes capriscus from the Gulf of Gabès, southern Tunisia, Mediterranean Sea, were estimated from the first dorsal spine sections of 463 specimens (206 males and 257 females), whose fork length was between 139 and 427 mm and the total weight ranged from 90.04 to 1967.41 g. The monthly percentage of specimens having a terminal translucent zone has indicated that the growth zone is formed once a year, during the cold season (February). The von Bertalanffy growth equations were: FL = 420.7 [1 − e−0.233(t + 0.123)] and FL = 417.0 [1 − e−0.238(t + 0.074)], for males and females, respectively. The longevity estimated was 13 years old for both sexes. The instantaneous mortality rates were estimated to 0.23 for males and 0.24 for females. The weight–length relationships of the grey triggerfish were Wt = 21.510−3 LF3.046 and Wt = 41.010−3 LF2.835, for males and females, respectively.

The fecundity of Gray Triggerfish Balistes capriscus has been difficult to estimate, as few imminently spawning or recently spawned females have been detected. Our study focused on verifying the pattern of oogenesis and fecundity type in Gray Triggerfish. During 1999–2012, females (n = 1,092) were collected from the eastern Gulf of Mexico, and subsets of these fish were used to calculate condition indices and assess ovarian histology. The gonadosomatic index, hepatosomatic index, and Fulton's condition factor indicated that liver and somatic energy stores increased prior to spawning and were depleted throughout the spawning period, characteristic of a capital pattern of energy storage and allocation to reproduction. Typical of a capital breeding pattern, we also observed (1) a hiatus in oocyte size distribution and (2) group-synchronous oogenesis, which are both traits of a determinate fecundity type. However, evidence that fecundity was not set prior to spawning included the observation of “de no...

Following the 2010 Gulf of Mexico oil spill, concerns were raised regarding exposure of fish to crude oil components, particularly polycyclic aromatic hydrocarbons (PAHs). This three year study examined hepatic enzymes in post-mitochondrial supernatant fractions from red snapper (Lutjanus campechanus) and gray triggerfish (Balistes capriscus) collected in the north central Gulf of Mexico between 2011 and 2014. Biomarker activities evaluated included benzo(a)pyrene hydroxylase (AHH), ethoxyresorufin O-deethylase (EROD), glutathione transferase (GST), and glutathione peroxidase (GPx). Mean EROD activity was higher in gray triggerfish (12.97 ± 7.15 pmol/min/mg protein [mean ± SD], n = 115) than red snapper (2.75 ± 1.92 pmol/min/mg protein, n = 194), p