Relatively few non-native species are known from coastal ecosystems at high latitudes to date. We examined the fouling community in Alaska for the presence of the marine amphipod Caprella mutica, which is native to the northwestern Pacific Ocean and has invaded many different global regions. Between 2000 and 2007, fouling panels were deployed in 6 sheltered, shallow bays in Alaska. C. mutica were detected on panels at 4 of these bays, ranging from southeastern Alaska (Ketchikan) to the Aleutian Islands (Dutch Harbor), and have been present in Alaska for at least 6 yr. This appears to be the first reported occurrence of a non-native marine species in the Aleutians and also the first confirmation that a non-native crustacean has established self-sustaining populations in Alaska. These data contribute to growing evidence that coastlines in Alaska are susceptible to biological invasions.

Trophic morphology plays a major role in niche diversification among the highly diverse fish fauna of coral reefs. It gives insight into feeding types and is useful in taxonomy, as it can be used to differentiate between species and to estimate phylogenetic relationships. The gobiid genus Gobiodon comprises obligate coral dwelling species that are widespread on Red Sea and Indo-Pacific reefs. Yet very little is known about their ecology and behaviour of feeding. In this study, viscerocranial and oral jaw morphology was investigated in seven species of Gobiodon that occur in the Red Sea. Osteological analyses were carried out on enzyme cleared and alizarin red stained specimens. Shape variation of the viscerocranium was analyzed using a landmark-based geometric morphometric method on digital scans of hand drawings and visualized in thinplate splines. Shape was determined by placing landmarks on skeletal elements in their articulated state. Morphology of the dentary and premaxilla was examined in further detail after disarticulation. A combination of landmarks and semilandmarks was applied to digital photographs of the oral jaws. It was shown that orbit size influences viscerocranial morphology by delimiting the lower jaw articulation angle. The premaxilla differs both in its extent and direction of curvature and in the structure of the articular process. Form changes in the dentary are mainly caused by variation of curvature and depth. A significant relationship between oral jaw shape and the number of anterior rows of teeth was found. Morphological diversity of selected elements is used to generate hypotheses concerning the trophic biology and niche diversification of Gobiodon. Brief dietary and in situ behavioural observations were carried out to further develop and test hypotheses.

Characteristics of the second gnathopod are traditionally used to distinguish between species of caprellid amphipods. However, these distinctions are often subjective and can be variable within a species. Geometric morphometrics were used to quantitatively assess shape variation of the second gnathopod propodus of three species of caprellids in North America, including the non-native Caprella mutica. Gnathopod shapes of C. mutica specimens from different latitudes revealed distinct morphologies; the factors responsible for the shape variations are unknown. Allometric change of propodus shape was observed in C. mutica. Larger individuals showed a wide array of possible propodus morphologies. Despite this variability, there were clear differences between large specimens of C. mutica and two species native to North America: C. alaskana and C. kennerlyi. The use of geometric morphometrics and the thin-plate spline method can serve to both complement descriptions using traditional keys and aid in identification of non-native species in novel geographical regions.