Graduation date: 1978

This investigation was carried out to characterize and quantitate the collagen of rockfish intramusclar connective tissue. Different species ot rocktish were chosen to represent the range of product quality experienced by the fish processing industry. Species included widow, a rockfish noted tor its soft flesh, yellowtail, a rockfish possessing flesh of intermediatary texture and canary rockfish known for its firm flesh. The intramuscular connective tissue collagen was extracted from white muscle and total, salt, acid and insoluble collagen content was estimated by hydroxyproline analysis. No significant difference was observed among species with regard to all collagen fractions. Mean salt, acid and unsoluble collagen contents were 5.5 %, 8.7 % and 86 %, respectively indicating a relatively highly crosslinked and stable collagen compared to that reported for other fish collagens. The denatured acid soluble collagen traction was characterized by chromatography on CM-cellulose and the presence of three different alpha chains was established by SDS-polyacrylamide gel electrophoresis and amino acid analysis of the collagen components. The molecular weight for the alpha chains was estimated to be 96,000 based upon agarose molecular sieve chromatography. The alpha chains, designated αl, α2 and α3, had significantly different amino acid composition with the α3 chain possessing a higher level of hydroxylated lysine than αl and α2. In general, the amino acid composition of rockfish muscle collagen was similar to other reported fish collagens. Digestion of purified connective tissue and acid soluble muscle collagen with CNBr and subsequent analysis by LDS-polyacrylamide slab-gel electrophoresis showed identical peptide patterns indicating the presence of only one molecular type of collagen. This evidence along with the observed ratio of the collagen components resolved by CM-cellulose chromatography supported a molecular composition of αl-α2-α3 for rockfish muscle connective tissue collagen. Significant difference in skin thickness between species was observed. This correlated with the general quality ranking of the three species by the fish processing industry of canary>yellowtail>widow. Skin from canary rockfish was 38 % thicker than skin from widow rockfish while yellowtail had a skin of intermediatary thickness. From this observation, it was concluded that skin thickness and strength plays a more important role than intramuscular connective tissue characteristics in determining quality of product obtainable from the different rockfish species. / Graduation date: 1984

El penegal, Helicolenus dactylopterus dactylopterus (Pisces: Scorpaeniformes), és una espècie que habita profunditats d'entre els 200 i 1000 m i presenta una clara distribució batimètrica en funció de la seva talla. Presenta fecundació interna i a l'interior de l'ovari conté estructures d'emmagatzematge que permeten emmagatzemar l'esperma durant períodes de temps considerablement llargs. Les cèl·lules sexuals masculines es mantenen viables gràcies a diverses substàncies nutritives que obtenen de la bossa citoplasmàtica i de l'epiteli criptal que delimita les estructures d'emmagatzematge. Aquest epiteli és també responsable de la seva protecció. Un cop els ous han assolit la maduresa, els espermatozoides són alliberats al lumen ovàric i es dóna la fertilització. És una espècie zigòpara: allibera òvuls fecundats que han estat retinguts al tracte reproductiu femení durant un curt període de temps i, per tant, els embrions són alliberats en estadis molt primerencs de desenvolupament. Així, el penegal presenta una estratègia reproductiva evidentment eficaç. / The bluemouth, Helicolenus dactylopterus dactylopterus (Pisces: Scorpaeniformes), is a species that inhabits the seabed at depths between 200 and 1000 m and shows a clear size-dependent bathymetric distribution.It has internal fertilization and, inside the ovary, there are storage structures that allow it to store sperm for considerably long periods of time. These male sexual cells remain viable thanks to several nutritious substances they obtain from the cytoplasmic bag and from the cryptal epithelium that delimits the storage structures. This epithelium is also responsible for their protection. Once the eggs have reached maturity, the spermatozoa are freed in the ovarian lumen and fertilization occurs. This species is zygoparous: liberation of fertilized ova, which have been retained in the female reproductive tract during a short period of time and, therefore, the embryos are freed in very early stages of development. Thus, the bluemouth exhibits an obviously effective reproductive strategy.