Labrus

Abstract: The family Labridae is a large assemblage of marine fish composed of about 580 species in 82 genera distributed in tropical and temperate marine waters around the world. Several subgroups, currently classified as tribes, have been identified in this large family, yet only a few phylogenetic analyses have been performed on labrid clades. We confirm monophyly of the labrid tribe Labrini and propose a phylogeny of the 23 species of the genera Acantholabrus, Centrolabras, Ctenolabrus, Labrus, Lappanella, Symphodus, Tautoga, and Tautogolabrus occurring in the eastern and western Atlantic and the Mediterranean. We analyzed a 577-bp segment of the mitochondrial 16S rDNA and a 506-bp segment of the mitochondrial control region in 22 species, for a total of up to 1069 bp per species. We used both parsimony and likelihood approaches under a variety of assumptions and models to generate phylogenetic hypotheses. The main features of the molecular phylogeny for the Labrini turned out to be the same for the two algorithms applied. The tree structure is similar to a previous, unpublished morphological phylogeny for a subset of labrine species. Estimated divergence times of the Labrini based on fossils and a molecular clock range from about 15 mya for the deepest splits to less than 1 mya for younger clades. Biogeographic patterns of the Symphodus species group and the genus Labrus are dominated by speciation events driven by the closing and opening of the Mediterranean Sea and periodic glaciation events during the past 1 million years. The Labrini are the only clade in the entire Labridae that exhibit nest-building and broodcare behavior. We use the phylogeny to show that similar broodcare behavior has evolved twice in the labrine fish and discuss scenarios for the evolution of broodcare from the diandric protogynous hermaphroditism found in ancestral labrines and many other wrasses.

Abstract: Predation on hatchery-reared lobsters (Homarus gammarus) in the wild was studied in order to identify pred- ators in southwestern Norway on rocky and sandy substrates in winter and summer. Lobsters of 12-15 mm carapace length were tagged with magnetic microtags. About 51 000 juvenile lobsters were released on 10 occasions at three lo- cations. Predator samplings were by trammel nets, eel traps, and videorecordings during the 24 h immediately follow- ing the releases. In summer, loss to predators occurred on both rocky and sandy substrates. The loss was lower in winter when lobsters were found as prey in predators caught on sand. The risk of fish predation was highest in the first hours after release, when the lobsters were out of shelter. The wrasses Labrus bergylta and Labrus mixtus were the major predators of lobsters, while Atlantic cod (Gadus morhua), shorthorn sculpin (Myoxocephalus scorpius), and crab (Cancer pagurus) were mainly winter predators. Winter predators were never as abundant as summer predators. To minimise predatory loss of reared and costly lobsters, they should be released onto rocky substratum in winter. Due to the damage to the predated lobsters, it was not possible to correlate survival against lobster size.