An opinion paper: emphasis on white muscle development and growth to improve farmed fish flesh quality

Due to rapid depletion of wild stocks, the necessity to cultivate fish is eminent. Current fish farming practices seek to improve flesh quality. The notion that white muscles are the main target of the fishing industry is emphasized. A novel approach is suggested based on the development of white muscles in wild fish from eggs to adults. A compilation of facts about white muscle structure, function and ontogeny is followed by an account of the changes in swimming behaviour and performance related to the use of white muscle during growth from larva to adult. Ecological data narrate early swimming performance with white muscle development and growth, unveiling some of the important natural selection factors eliminating weak swimmers and poor growers from the breeding stock. A comparison between fish culture practise and natural conditions reveals fundamental differences. New approaches following wild breeding processes promise several important advantages regarding the quality of white muscle

The distribution patterns of Red Sea Chaetodontid assemblages

1. The occurrence and abundance of butterflyfishes were investigated in northern, central and southern areas of the Eritrean Red Sea coast. Visual census was used to estimate the presence and abundance of the species along 100-metre long transects. 2. The assemblages of buttertlyfishes from the three areas differ markedly. Two species are restricted to the north, while three others occur only in the south. The central area contains six species occurring in both the south and the north. 3. The results show that the chaetodontid assemblage of the northern area is more related to the central and northern region of the Red Sea while the southern area has many species in common with the Gulf of Aden. 4. The areas, sampled, are considered to represent different biogeographic regions within the Red Sea. It has been suggested that a barrier exists in the Red Sea, which prevents dispersal between the northern and southern regions. Our results indicate that this barrier is situated in the Eritrean central area. The nature of this barrier, however, remains unclear. Copyright (c) 2005 John Wiley & Sons, Ltd

Growth of Chaetodon larvatus (Chaetodontidae: Pisces) in the southern Red Sea

Growth and age of Chaetodon larvatus were studied using growth bands in otoliths and length-frequency analyses. Otoliths of 180 C. larvatus were extracted and measured. Polished sections of sagittae revealed alternating opaque and translucent bands corresponding with a seasonal growth pattern. Both mass and size of the otoliths continue to grow steadily throughout life. Length-at-age data revealed very fast growth during the first year. Growth proceeded at a decreasing rate during the second and the third year; fishes older than 3 years did not grow noticeably. No difference in growth patterns between males and females could be detected. The growth parameters obtained for the whole population are: the asymptotic length (L-infinity)=10.64 cm, growth constant (K)=1.14 year(-1) and the theoretical age at length zero (t(0))=-0.30 year. The maximum age recorded was 14 years. Length frequency data collected at a recruitment site confirmed the fast growth of juveniles

Dietary overlap among coral-feeding butterflyfishes (Chaetodontidae) at Lizard Island, northern Great Barrier Reef

This study documented the range of corals,\ud and other prey types, consumed by 20 species of but-\ud terflyfishes, which co-occur at Lizard Island, northern\ud Great Barrier Reef, Australia. Six species (Chaetodon\ud aureofasciatus, C. baronessa, C. lunulatus, C. plebius,\ud C. rainfordi and C. trifascialis) fed almost exclusively\ud on scleractinian corals, and a further eight species\ud (C. citrinellus, C. kleinii, C. lunula, C. melannotus,\ud C. rafflesi, C. speculum, C. ulietensis,and C. unima-\ud culatus) took a significant proportion of their bites\ud from corals. The other six species (C. auriga, C. ep-\ud hippium, C. lineolatus, C. semeion, C. vagabundus, and\ud Chelmon rostratus) rarely consumed coral, but fed on\ud small discrete prey items from non-coral substrates.\ud Coral-feeding butterflyfishes consumed a wide range of\ud corals. Chaetodon lunulatus, for example, consumed 51\ud coral species from 24 different genera. However, there\ud was up to 72% dietary overlap between coral-feeding\ud butterflyfishes, with 11/14 species feeding predomi-\ud nantly on Acropora hyacinthus or Pocillopora dami-\ud cornis. The most specialised corallivore, C. trifascialis,\ud took 88% of bites from A. hyacinthus. Chaetodon tri-\ud fascialis defend territories encompassing one or more\ud colonies of A. hyacinthus, and may have prevented\ud other species such as C. lunulatus from feeding even\ud more extensively on this coral. This study has shown\ud that coexistence of coral-feeding butterflyfishes occurs\ud despite an apparent lack of partitioning of prey\ud resources. While different coral-feeding butterflyfishes\ud were more or less selective in their use of different coral prey, virtually all species fed predominantly on\ud A. hyacinthus or P. damicornis