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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).

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.

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.

Gelatin was extracted from the skin of grey triggerfish (Balistes capriscus) by the acid extraction process with a yield of 5.67 g/100 g skin sample on the basis of wet weight. The chemical composition and functional properties of gelatin were investigated. The gelatin had high protein (89.94 g/100 g) but low fat (0.28 g/100 g) contents. Differences in the amino acid composition between grey triggerfish skin gelatin (GSG) and halal bovine gelatin (HBG) were observed. GSG contained a lower number of imino acids (hydroxyproline and proline) (176 residues per 1000 residues) than HBG (219 residues per 1000 residues), whereas the content of serine was higher (40 versus 29 residues per 1000 residues, respectively). The gel strength of the GSG (168.3 g) was lower than that of HBG (259 g) (p < 0.05) possibly due to lower hydroxyproline content. Grey triggerfish skin gelatin exhibited a slightly lower emulsifying activity and water-holding capacity but greater emulsifying and foam stability, foam formation ability and fat-binding capacity than the halal bovine gelatin (p < 0.05). SDS-PAGE of GSG showed high band intensity for the major protein components, especially, α- and β-components and a similar molecular weight distribution to that of standard calf skin collagen type I.

A highly alkaline trypsin from the intestine of Grey triggerfish ( Balistes capriscus ), with high activity at low temperature, was purified and characterised. The enzyme was purified to homogeneity using acetone precipitation, Sephadex G-100 gel filtration and Mono Q-Sepharose anion-exchange chromatography, with a 13.9-fold increase in specific activity and 41.3% recovery. The molecular weight of the purified alkaline trypsin was estimated to be 23.2 kDa by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE) and size exclusion chromatography. Purified trypsin appeared as a single band on native–PAGE. Interestingly, the enzyme was highly active over a wide range of pH, from 9.0 to 11.5, with an optimum at pH 10.5, using Nα -benzoyl-DL-arginine- p -nitroanilide (BAPNA) as a substrate. The relative activities at pH 9.0, 11.5 and 12.0 were 86.5%, 92.6% and 52.4%, respectively. The enzyme was extremely stable in the pH range 7.0–12.0. In addition, the enzyme had high activity at low and moderate temperatures with an optimum at around 40 °C and had more than 80% of its maximum activity at 20 °C. The purified enzyme was strongly inhibited by soybean trypsin inhibitor (SBTI) and phenylmethylsulphonyl fluoride (PMSF), a serine protease inhibitor. The enzyme showed extreme stability towards oxidising agents, retaining about 87% and 80% of its initial activity after 1 h incubation at 40 °C in the presence of 1% sodium perborate and 1% H 2 O 2 , respectively. In addition, the enzyme showed excellent stability and compatibility with some commercial solid detergents. The N -terminal amino acid sequence of the first 12 amino acids of the purified trypsin was IVGGYECTPNST . B. capriscus trypsin, which showed high homology with trypsins from marine vertebrates, had a basic residue, Asn, at position 10, where His and Tyr are common in all marine vertebrates trypsins. The trypsin kinetic constants, K m and k cat for BAPNA, were 0.068 mM and 2.76 s −1 , respectively, while the catalytic efficiency, k cat / K m , was 40.6 s −1 mM −1 .

Fishing disturbance can have indirect negative effects on animal behavior and survival, but receives little attention compared to measures of direct fisheries extraction. We quantified changes in the density of Caribbean spiny lobster Panulirus argus when exposed to experimental human disturbance and injury typical of sport-diver harvest attempts in the field. A complementary study in a large seawater arena quantified lobster sheltering behavior and survival when exposed to the single and combined effects of human disturbance and triggerfish Balistes capriscus predators. Human disturbance and injury of lobsters in the field caused lobsters to emigrate from shelters that had been typically occupied over successive days. Similarly, both the presence of triggerfish predators and human disturbance promoted decreased lobster shelter fidelity to individual shelters in the arena. Overall shelter use and gregariousness increased in the presence of natural triggerfish predators but not as a function of human disturbance. Decreased shelter use and gregariousness by lobsters when exposed to human disturbance may have contributed to their decreased survival when exposed simultaneously to triggerfish. These results highlight how human disturbance and injury of lobsters can alter their behavior and reduce subsequent survival in the presence of their natural predators, and illustrate the need to incorporate the negative effects of sport-divers into models that estimate population demographic rates.

The vasorelaxing activity of the aqueous extract of fish Balistes capriscus skin (AEBc) on mesenteric arterial bed (MAB) of rats was studied. The bolus injections of AEBc (bolus of 5.1, 10.2, 20.5, and 41.1mg) significantly inhibited, in a concentration-dependent manner, the maximal contractile response induced by methoxamine (30 microM) in MAB. The vasodilatation action of AEBc is not mediated through beta-adrenoceptors or cyclo-oxigenase, since it was not affected by propranolol (20 microM) or diclofenac sodium (3 microM). The vasodilator response induced by subsequent addition of AEBc Balistes capriscus in bolus was significantly reduced in water infusion for endothelium removal. Treatment with an inhibitor of NO synthase (L-NAME, 10 microM) decreased AEBc effect. The guanylate cyclase inhibitor methylene blue (MB, 100 microM) had no significant effect on AEBc-induced vasodilatation. These results suggest that the vasorelaxing effect of AEBc is mediated by endothelium-dependent (NO/EDRF) and endothelium-independent neurally induced vasorelaxation from nonadrenergic and noncholinergic nerves (NO).

Opaque rings on sectioned otoliths and sectioned dorsal spines were used to age yellowtail snapper, Ocyurus chrysurus ( N = 654) and queen triggerfish, Balistes vetula ( N = 665), taken from U.S Virgin Islands and Puerto Rico trap and hook-and-line fisheries in 1983 and 1984. Annulus formation, validated by marginal increment analysis, occurred from March to May for yellowtail snapper and from February through March for queen triggerfish. The maximum age for yellowtail snapper was 17 years, compared with only 7 years for queen triggerfish. Mean back-calculated fork lengths ( FL , mm) of yellowtail snapper aged 1, 5, 10, 15 and 17 years were 117, 287, 375, 455 and 505, respectively. Mean back-calculated lengths for queen triggerfish aged 1–7 years were 161, 229, 274, 307, 332, 356 and 378 mm FL , respectively. The von Bertalanffy growth equations for yellowtail snapper and queen triggerfish were L t =502.5 (1−e −0.139( t + 0.955) ) and L t =415(1− e −0.30( t + 0.600) ) respectively, where t = age in years. The length-weight relationship for yellowtail snapper was W = 0.000117 FL 2.6504 , where W = weight in grams and was W = 0.000101 FL 2.750 for queen triggerfish. Data revealed that yellowtail snapper live longer than previously reported and grow at a rate similar to other western Atlantic lutjanids. Queen triggerfish studied were not as old as expected, probably because of fishing gear selectivity.

1. 1. A comparative study of the liver sterols found in male and female channel catfish ( Ictalurus punctatus ), vermilion snapper ( Rhomboplites aurorubens ), and gray triggerfish ( Balistes capriscus ) was conducted. 2. 2. Cholesterol was the only sterol present in all the livers analyzed. Squalene was observed in relatively minor amounts. 3. 3. Liver cholesterol levels in the female channel catfish were found to be higher than in other fish studied.