Members of the Epinephelinae subfamily of serranids (‘grouper’) are heavily exploited by bottom longline in the Gulf of Gabès located in the south of Tunisia. In addition to direct mortality, hook and release mortalities likely occur when fish are caught and released, due to injuries sustained from hooking as well as those associated with retrieval. During five experimental trips (29 fishing sets) conducted in August 2011 from the port of Djerba (south of the Gulf of Gabès), we evaluated the effect of hook styles (9/0 ‘J’ and 12/0 circle hook) on groupers and non-target species. A total of 340 specimens representing 10 species were captured. The higher catch rate was registered for Epinephelus aeneus. The majority of groupers captured were female mature. The circle hook increased the capture of the most common grouper E. aeneus and did not affect the catch of Epinephelus marginatus and Epinepheleus costae. The effect of the type of hook on hooking location was inconclusive. Managing of the grouper fishery using some management actions such as size limits, bag limits, and closed seasons may prevent more unnecessary losses of grouper species. From this preliminary study, a definite conclusion for or against the use of circle hook cannot be drawn. Further research on the role of gear modification and hook designs in reducing by-catch, hooking-related injury and mortality should be encouraged.

The common dolphinfish (Coryphaena hippurus) is widely distributed and represents an important part of the currently exploited fishery resources. This species’ feeding behaviour, however, is poorly understood. This study aimed to investigate the feeding behaviour of dolphinfish and the effect of body size (and the consequently aggregated learning experience) on the strategies used for capturing their prey. Observations were made from an oil platform in north-eastern Brazil. Dolphinfish length was visually estimated and classified into three size classes. The following foraging strategies were observed in our study: ‘active chasing’, ‘leaping out’, ‘swimming in circles’, ‘surf’, ‘using floating objects’ and ‘cleaning turtle carapaces’. The most frequently used foraging strategy was ‘active chasing’, suggesting a strong preference of dolphinfish in using visual cues during predation. Smaller size-classes of dolphinfish did not perform the ‘swimming in circles’ and ‘surf’ strategy, probably due to a lack of learning experience, since further social interactions could be needed in order to show this strategy. Smaller dolphinfish regularly showed the ‘using floating objects’ as a foraging strategy, probably reflecting an opportunistic behaviour. The smallest individuals were using more simple strategies, to chase smaller prey that could have different and less complex escape strategies. It indicates learning experience could play an important role into the dolphinfish ontogeny, moving towards more complex foraging strategies throughout their lives. Independently of the age class, the dolphinfish displayed a varied repertory of foraging strategies, maximizing hunting success in the open ocean, a hostile pelagic environment with a low prey availability.

Dugong Dugong dugon Lacépède, 1799, a globally threatened marine mammal that occurs in the coastal waters of the Indian and Pacific Ocean, is traded in small numbers throughout their range. We surveyed 128 shops selling wildlife in seven (June 2013) and eight (July 2014) towns on the island of Bali, one of Indonesia's most popular tourist destinations. Dugongs are protected under Indonesian law and CITES Appendix I Iisting precludes international trade. Despite this dugong parts were observed in trade in Denpasar, Mengwi and Sanur where 14 traders were interviewed. We recorded over 130 dugong parts, including raw bones and teeth but also many carved items and some derivatives, with no noticeable difference between years. The most common items were cigarette pipes carved from, predominantly, dugong ribs, and decorative carvings from bone and teeth. The total value of the items observed was $1500–3000. The trade was open and qualitatively similar to trade in parts of non-protected species. Information from traders suggests that dugongs are caught throughout Indonesia, and are both targeted specifically and caught accidentally. It is imperative for the management of dugongs to take the illegal trade in dugong parts into account and for the authorities to curb the trade by taking appropriate action in line with Indonesia's legislation. Greater awareness of the plight of the dugong, including the impediments to their conservation posed by the illegal trade in body parts, by the residents of and visitors to Bali, may aid in pressuring the authorities to take these steps.

Seasonal distribution and abundance of anchovy eggs were analysed during three scientific cruises carried out from summer 2006 to summer 2007 in the Boka Kotorska Bay, and one cruise in July 2008 in the open waters of the south-eastern Adriatic Sea. Daily egg production method (DEPM) was applied for the first time for estimation of the anchovy spawning stock biomass in the south-eastern Adriatic Sea. The daily egg production was 13–581 eggs day−1 within the bay, and 42–110 eggs day−1 in the open waters. Anchovy egg abundance was highest in spring inside the Bay of Kotor (one of the innermost and eutrophic sub-bays of the Boka Kotorska Bay), which indicates that the conditions for anchovy spawning are very favourable in this part of the Adriatic Sea, even when temperatures are below the optimum. This study has shown that the Boka Kotorska Bay is an area of very intensive spawning of anchovy, and that small-size anchovies live and spawn in the bay, and after spawning migrate towards open waters. The length at which 50% of anchovy were mature (L50) was calculated as 9.28 for females and 9.02 for males. Spawning stock biomass was at a stable level during the period of investigation.

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.