Scientia Marina

From the Mediterranean to Antarctica: The Scientific Journey of Josefina (Pepita) Castellví Piulachs (1935-2026)

2026-02-16T16:21:30+01:00

GIS-based multicriteria analysis for on-bottom aquaculture of the sea scallop, Placopecten magellanicus, in St Pierre and Miquelon, a sub-Arctic French archipelago (NW Atlantic)

2025-09-18T11:28:56+02:00

The seafood industry of Saint Pierre and Miquelon (SPM) was severely impacted by the collapse of the Eastern Canadian cod fishery, which led to the 1992 moratorium. This underscored the need for diversification strategies to sustain the local economy. Scallop aquaculture (Placopecten magellanicus) has since been developed on a limited scale, but spatial expansion is required to ensure long-term economic viability. In 2008, a comprehensive research and development programme was launched to address this need. This study focuses on the critical stage of site selection, applying a GIS-based multi-criteria approach to identify suitable areas for on-bottom scallop aquaculture. Acoustic and video surveys, combined with ground-truthing, produced the first large-scale seabed habitat maps of eastern SPM. These maps also provide a geospatial database to support coastal zone management and decision-making in the archipelago. The results identified 8335 ha suitable for aquaculture, subdivided into areas for public stock enhancement and leasing grounds for private operations. Suitable areas are not a limiting factor for expansion, and a 2724-ha zone was identified as the most appropriate for leasing, supporting a potential annual production of ~100 t, based on existing equipment and a current five-year rearing cycle at 4 ind. m–². Habitat characterization also enables optimal matching of dredge types (New Bedford vs toothed crossbar) to seabed conditions, minimizing future benthic impacts. Management recommendations and research priorities are discussed, with particular emphasis on addressing the availability of juveniles for seeding. Large-scale development is constrained by juvenile supply, necessitating optimization of spat collection and/or hatchery production. These findings lay the foundation for a strategic aquaculture growth plan, positioning scallop farming as a key contributor to the long-term economic resilience of the SPM archipelago alongside traditional fisheries.

Reproductive biology of the Chilean eagle ray, Myliobatis chilensis (Myliobatiformes: Myliobatidae), disembarked in the port of Salaverry, Peru

2025-04-10T16:38:27+02:00

Myliobatis chilensis, commonly known as the Chilean eagle ray, is a benthopelagic species found along the Humboldt Current. Peruvian fisheries target it, but little is known about its life history. This study aimed to gather information on the reproductive biology of M. chilensis from Salaverry. A total of 160 individuals from monthly landings between October 2017 and November 2018 were analysed, with data collected on sex, disc width (DW), clasper calcification, weight, liver and gonads. Sexual maturity was determined by comparing clasper length and clasper calcification in males and by gonadal structure in females. Eighty male individuals (41–153 cm DW) and 80 female individuals (42–221.6 cm DW) were obtained, yielding a sex ratio of 1F:1M. The average ovarian fertility was 32 oocytes, and the median size at sexual maturity was estimated to be 163 cm DW for females and 122 cm DW for males. Histological samples were processed by inclusion in paraplast and stained with haematoxylin and eosin for corroboration. Five stages of ovum development and 11 stages of spermatozoan development were observed. Based on these microstructural observations, a maturity scale with easily distinguishable stages was constructed. The study found that gonads are the sole indicators of maturity in females, while claspers serve as excellent indicators in males. Only mature ovaries were sampled from the second half of each year, and no embryos were found. These reproductive insights are expected to assist in decision-making for sustainable management.

Multidecadal tag recoveries of loggerhead turtles nesting in Greece reveal their foraging areas in the Mediterranean

2025-10-28T19:46:40+01:00

Tag recoveries from a more than 40-year tagging programme of loggerhead turtles nesting at the three major nesting areas of Greece (Zakynthos, Kyparissia Bay, Rethymno) revealed their post-nesting whereabouts in the Mediterranean. Most tag recoveries, signalling potential foraging areas, occurred in the Central Mediterranean, with major concentrations in the Adriatic Sea and the Tunisian Plateau (both characterized by shallow waters and rich benthic fauna), whereas fewer recoveries were recorded in the Aegean Sea. While turtles from Zakynthos and Kyparissia Bay shared the Adriatic Sea and the Tunisian Plateau, turtles from Rethymno (Crete) preferred the Aegean Sea and the Levantine Sea. Tag recoveries showed a much wider dispersal of post-nesting turtles than the dispersal recorded from satellite telemetry, highlighting the benefits of long-term tagging programmes. More than 60% of the recovered turtles were reported dead, indicating the substantial threats that reproductively active individuals, the most biologically valuable group in the loggerhead population, face in the Mediterranean Sea.