Effects of Vacuum and Modified Atmosphere Packaging on the Quality and Shelf-Life of Gray Triggerfish (Balistes capriscus) Fillets

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* >> 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’ 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.

Estimating population abundance at a site in the open ocean: combining information from conventional and telemetry tags with application to gray triggerfish (Balistes capriscus)

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.

DESENVOLVIMENTO E CARACTERIZAÇÃO FÍSICO-QUÍMICA DE HIDROLISADO PROTEICO DE PEROÁ (Balistes capriscus) PRODUZIDO A PARTIR DE COPRODUTOS

O processo de hidrólise enzimática pode ser um método viável para usar os coprodutos da indústria pesqueira, como um recurso potencial e não descartado. O hidrolisado de proteína de peixe produzido a partir de peroá (Balistes capriscus), como coprodutos oferece uma alternativa à indústria. Portanto, o objetivo deste trabalho foi fornecer uma proteína de peroá hidrolisada, além de descrever os parâmetros físico-químicos, avaliando o grau de hidrólise (GH) e suas propriedades funcionais (solubilidade, índice de estabilidade de emulsão e índice de atividade emulsificante). Assim, o processo de hidrólise enzimática de peroá foi conduzido seguindo um planejamento fatorial com duas variáveis independentes: tempo (minutos) e concentração de enzima (% p:v). Neste contexto, foi avaliada uma composição centesimal e grau de hidrólise (GH) de todas as formulações. Além disso, solubilidade, índice de estabilidade de emulsão (IEE) e índice de atividade emulsificante (IAE) para formulações com GH maior que 50%, também foram avaliados. Considerando as análises de composição centesimal da matéria-prima, foram obtidos os seguintes resultados: umidade 78,32 ± 0,05 e 87,36 ± 0,46; cinzas: 6,54 ± 0,53 e 3,66 ± 0,69; lipídios: 5,19 ± 0,71 e 5,91 ± 0,71; proteínas: 6,66 ± 0,02. Portanto, considerando uma análise de superfície de resposta, foi demonstrado que é possível obter o mesmo percentual de grau de hidrólise em menor tempo e concentração de enzima, tornando- se um processo mais econômico. As formulações F-1, F-5 e F-7 foram considerados os melhores resultados, devido ao maior índice de solubilidade e índice de estabilidade de emulsão (p <0,05).

Recreational fishers consistently inform about different meridionalization dynamics of two Mediterranean subregions

Marine recreational fishers accumulate a vast amount of Local Ecological Knowledge (LEK) during their fishing activity that can be of paramount importance for monitoring how climate change affects the structure of biological communities. Here, we accessed the LEK of recreational anglers and recreational spearfishers to investigate the increase in the abundance of five northward expanding indigenous thermophilic fish species in two subregions of the Mediterranean Sea: the Adriatic/Ionian Seas and the Tyrrhenian/Ligurian Seas. We used an online survey administered through Twitter and Facebook between 2017 and 2018 to both Italian and Croatian recreational fishers. A total of 794 respondents completed the questionnaire (386 from the Adriatic/Ionian subregion and 408 from the Tyrrhenian/Ligurian one). Overall, the species perceived as most increasing in abundance were Pomatomus saltatrix (71% of replies) followed by Sphyraena viridensis (58%). The rest of species (Coryphaena hippurus, Balistes capriscus and Sparisoma cretense) ranged between 17% and 25%. We showed that recreational fishers have a stable system of beliefs about meridionalization, which is perceived homogeneously between recreational anglers and spearfishers. Moreover, our results indicate that latitude is negatively correlated with meridionalization in the Adriatic/Ionian, but not in the Thyrrenian/Ligurian Seas, suggesting that meridionalization of the Adriatic/Ionian Seas could be a process that is temporally lagged with respect to the Tyrrhenian/Ligurian Seas. Our study demonstrate that LEK of specific target groups such as recreational fishers can be easily accessed on large geographical scale and it can be useful to identify those fish species who are regarded as indicators of climate change.