A Simulation Method for Predicting Future Population Dynamics with Uncertainty

Unfortunately, most of the stocks are damaged by natural disasters or human activities and rebuilding the stock are urgent requirements. Until now, in the stock management, some policies are commonly believed to valid but have not been confirmed. A simulation model of the population dynamics incorporating uncertainty has been already made by the authors. The typical believes of the stock management, “Ban rebuild stocks”, “Large mesh rebuild stocks” were confirmed by the simulation model. Six stocks were randomly chosen mainly from the data of ICES for applying this simulation model. For applying the management policy of 1 year ban, 5 to 6 stocks had not significant effect compare with no regulation after around 5 years of the opening of the fishery. For 3 of 6 stocks, the effect of the enlarged the mesh size was not detected. In conclusion, the widely believed policies were valid for only a part of stocks. Thus the effects of the management policies should be confirmed before conducting and applying to stocks

DATA AND INITIAL MODEL SET-UP FOR THE 2022 STOCK SYNTHESIS STOCK ASSESSMENT OF THE EASTERN ATLANTIC AND MEDITERRANEAN BLUEFIN TUNA

This document describes the data used for Stock Synthesis assessment for the Eastern Atlantic and Mediterranean bluefin tuna. The initial model configuration, fleet definitions, selectivity modeling and main parameterization are also outlined. The model runs from 1950 to 2020 and is fit to length composition data and pair age-length data treated as conditional age-at-length.En prens

Effect of Tween Series on Growth and cis-9, trans-11 Conjugated Linoleic Acid Production of Lactobacillus acidophilus F0221 in the Presence of Bile Salts

Cis-9, trans-11 conjugated linoleic acid (c9, t11 CLA) producing bacteria have attracted much attention as novel probiotics which have shown beneficial effects on host health. However, bile salts are able to inhibit bacterial growth and c9, t11 CLA production. For recovering growth and c9, t11 CLA production of Lactobacillus acidophilus F0221 in the presence of bile salts, Tween series (Tween 20, Tween 40, Tween 60 and Tween 80) were added in growth culture containing 0.3% oxgall. Results showed that the viable counts were significantly (P < 0.05) recovered to 8.58–8.75 log CFU/mL in the presence of all Tween treatments. However, recovery of c9, t11 CLA production was only demonstrated in the presence of Tween 80 (72.89 μg/mL). Stepwise increasing oxgall in a concentrations range from 0.1% to 0.9% according to human intestinal physiological environments, Tween 80 still showed significant (P < 0.05) recovery ability on growth (8.91–8.04 log CFU/mL) and c9, t11 CLA (69.22–34.27 μg/mL) production. The effect of Tween 80 on growth and production was also investigated in the presence of different types of bile salts (sodium salts of cholic acid (CA), deoxycholic acid (DCA), chendeoxycholic acid (CDCA), glycocholic acid (GCA) and taurocholic acid (TCA)). Results showed that Tween 80 could significantly (P < 0.05) recover c9, t11 CLA production in the presence of all types of bile salts, but the Tween 80 could only significantly (P < 0.05) recover viable counts of the strain in the presence of CA, DCA and CDCA. This recovery ability could be attributed to the protection of leakage of intracellular material. Additionally, although bile salts inhibited growth and c9, t11 CLA production by the growing cell, it promoted the c9, t11 CLA production by the resting cell

Structure and estimation framework for Atlantic Bluefin tuna operating models.

A preliminary spatial, multi-stock statistical catch-at-length assessment model is developed as a basis for defining operating models for Atlantic bluefin tuna. The modifiable multi-stock model (M3) aims to improve upon previous multi-stock models such as MAST (Taylor et al. 2011) in three core areas. The first iteration of the model: (1) makes use of indices of abundance specific to time-area strata (e.g. for a given ocean area and month of the year), (2) does not use conventional tagging data to inform exploitation rates, (3) is fitted to samples of length composition data and therefore avoids established problems related to ageing individuals based on a growth curve and length data only. In this paper we provide a full account of preliminary M3 model equations and discuss the results of simulation evaluations of model estimation performance. Limitations of the current approach and future areas for model development are also discussed

Crossing the line: migratory and homing behaviours of Atlantic bluefin tuna

Assessment and management of Atlantic bluefin tuna Thunnus thynnus populations is hindered by our lack of knowledge regarding trans-Atlantic movement and connectivity of east- ern and western populations. Here, we evaluated migratory and homing behaviors of bluefin tuna in several regions of the North Atlantic Ocean and Mediterranean Sea using chemical tags ( δ 13 C and δ 18 O) in otoliths. Significant emigration of bluefin tuna from their place of origin was inferred from otolith δ 13 C and δ 18 O, with both eastern and western bluefin tuna commonly ‘crossing the line’ (45° W management boundary) in the Central North Atlantic Ocean and mixing with the other population. Several western migrants were also detected in Moroccan traps off the coast of Africa, indicating that trans-Atlantic movement occurs for members of the western population; however, the degree of mixing declined with proximity to the eastern spawning area (Mediterran- ean Sea). The origin of bluefin tuna collected at the entrance to the Strait of Gibraltar and from several regions within the Mediterranean Sea (Balearic Islands, Malta, and Sardinia) was essen- tially 100% eastern fish, demonstrating that natal homing is well developed by the eastern popu- lation, with western migrants rarely entering the Mediterranean Sea.Postprin

Crossing the line: migratory and homing behaviors of Atlantic bluefin tuna

Assessment and management of Atlantic bluefin tuna Thunnus thynnus populations is hindered by our lack of knowledge regarding trans-Atlantic movement and connectivity of eastern and western populations. Here, we evaluated migratory and homing behaviors of bluefin tuna in several regions of the North Atlantic Ocean and Mediterranean Sea using chemical tags (delta C-13 and delta O-18) in otoliths. Significant emigration of bluefin tuna from their place of origin was inferred from otolith delta C-13 and delta O-18, with both eastern and western bluefin tuna commonly 'crossing the line' (45 degrees W management boundary) in the Central North Atlantic Ocean and mixing with the other population. Several western migrants were also detected in Moroccan traps off the coast of Africa, indicating that trans-Atlantic movement occurs for members of the western population; however, the degree of mixing declined with proximity to the eastern spawning area (Mediterranean Sea). The origin of bluefin tuna collected at the entrance to the Strait of Gibraltar and from several regions within the Mediterranean Sea (Balearic Islands, Malta, and Sardinia) was essentially 100% eastern fish, demonstrating that natal homing is well developed by the eastern population, with western migrants rarely entering the Mediterranean Sea