Negative effect of ectoparasite burdens on the condition factor from farmed tilapia Oreochromis niloticus in the Yucatan, Mexico.

Nile tilapia (Oreochromis niloticus Linnaeus, 1758) is one of the most important aquaculture species in the world, and, when introduced, the ectoparasites of Nile tilapia have followed. Currently, farmers worldwide consider these ectoparasites harmless, but intensities can reach up to 1000 individuals per fish in tropical regions. In this cross-sectional study, we used the condition factor to estimate the potential effects of low (45 ± 31 ectoparasites per fish) and high (295 ± 191) ectoparasitic burdens across 28 tilapia farms and included the analysis of the effects of 44 management and environmental variable from the farms.

Insights on the biology and ecology of the deep-water shrimp Parapontophilus occidentalis (Faxon, 1893) (Crustacea: Caridea: Crangonidae) in the eastern Pacific with notes on its morphology.

The deep-water crangonid Parapontophilus occidentalis (Faxon, 1893) is endemic to the eastern Pacific and has been reported from Mexico to Chile, in depths of 837-4082 m. Material collected off the west coast of the Baja California Peninsula (BCP) during the TALUD XV, XVI and XVI-B cruises consists of a series of 136 specimens (M:F = 1:3.6) with 30 % of ovigerous females.

Distribution of Benthesicymustanneri Faxon, 1893 (Dendrobranchiata, Benthesicymidae) off the west coast of Mexico and notes on its morphology.

A large series of specimens of Benthesicymustanneri Faxon, 1893 (Dendrobranchiata; Benthesicymidae) was collected during an extensive survey of deep-water invertebrate fauna off western Mexico. In total, 61 males and 122 females (M:F ratio = 1:2) from 44 sampling stations were examined, considerably increasing the number of known specimens and sampling localities for this species which is widely distributed along the Pacific coast of Mexico. The collection is the largest available for this species to date and presents first records from off the west coast of the Baja California Peninsula and a slight increase of the northernmost record within the Gulf of California.

Trophic ecology of Lampanyctus crocodilus on north-west Mediterranean Sea slopes in relation to reproductive cycle and environmental variables.

This study examined the population structure, reproductive cycle and feeding pattern of the lanternfish Lampanyctus crocodilus in the Balearic Basin (north-west Mediterranean Sea) from a depth of 450 to 1800 m and at a seasonal scale. Juveniles were mainly located at shallower depths, but also at deepest stations in autumn, while adults mostly inhabited intermediate depths with their centre of population density (CPD) located at 800-1000 m of depth. The migration of adults to deeper depths was detected in late summer to autumn, probably linked to the occurrence of nepheloid layers at c.

Xenobiotic metabolism markers in marine fish with different trophic strategies and their relationship to ecological variables.

Nine fish species of commercial interest from six teleost families and two species of elasmobranchs were selected for characterisation of hepatic biomarkers used in early-warning assessment of pollutant exposure. The sampling was carried out in front of the Barcelona coast (NW Mediterranean) during December 2006 at shelf (53 m) and slope (660 m) depths. The enzymes considered included the antioxidant defence catalase (CAT) and glutathione reductase (GR), phase I ethoxyresorufin O-deethylase (EROD) and phase II glutathione S-transferase (GST).