Pamela J. Woods

Resource polymorphism and diversity of Arctic charr Salvelinus alpinus in a series of isolated lakes

Morphological, dietary and life-history variation in Arctic charr Salvelinus alpinus were characterized from three geographically proximate, but isolated lakes and one large lake into which they drain in south-western Alaska. Polymorphism was predicted to occur in the first three lakes because S. alpinus tend to become polymorphic in deep, isolated lakes with few co-occurring species. Only one morph was evident in the large lake and two of the three isolated lakes. In the third isolated lake, Lower Tazimina Lake, small and large morphs were found, the latter including two forms differing in growth rate. The small morph additionally differed from the two large forms by having more gill rakers and a deeper body than same-sized individuals of the large morph, consuming more limnetic and fewer benthic resources, having a greater gonado-somatic index and maturing at a smaller size. The two large forms consumed only slightly different foods (more terrestrial insects were consumed by the medium-growth form; more snails by the high-growth form). Trends in consumption of resources with body shape also differed between lakes. Variability in life history of S. alpinus in these Alaskan lakes was as broad as that found elsewhere. This variability is important for understanding lake ecosystems of remote regions where this species is commonly dominant.

Habitat-dependent geographical variation in ontogenetic allometry of the shiner perch Cymatogaster aggregata Gibbons (Teleostei: Embiotocidae)

Studies of intraspecific morphological variation in fishes have traditionally focused on freshwater rather than marine species. In addition, such studies typically focus on adults, although causes and intensities of selective pressures most likely vary through an individuals lifetime. In this study, body and head shape of a marine species, shiner perch Cymatogaster aggregata Gibbons were compared among localities along the Pacific Northwest coast of North America. Evidence was found for intraspecific variation in ontogenetic allometry, and for a closer correlation of body shape with environment rather than geographical proximity. This correlation with environment was more evident in younger fish, thereby demonstrating the importance of analysing multiple life stages. A common garden experiment suggests both environmental and genetic bases for the observed differences. Recognizing intraspecific ecomorphological complexity and its specificity to habitat and/or life stage can have important consequences for understanding the role of local adaptation and population dynamics in macroecology.

Variability in the functional role of Arctic charr Salvelinus alpinus as it relates to lake ecosystem characteristics

This study investigated how dietary habits vary with lake characteristics in a fish species that exhibits extensive morphological and ecological variability, the Arctic charr Salvelinus alpinus. Iceland is a hotspot of geological activity, so its freshwater ecosystems vary greatly in physical and chemical attributes. Associations of dietary items within guts of charr were used to form prey categories that reflect habitat-specific feeding behavior. Six prey categories were defined and dominated by snails (Radix peregra), fish (Gasterosteus aculeatus), tadpole shrimp (Lepidurus arcticus), chironomid pupae, pea clam (Pisidium spp.), and the cladoceran Bosmina sp.. These reflected different combinations of feeding in littoral stone, offshore benthic, and limnetic habitats. Certain habitat-specific feeding strategies consistently occurred alongside each other within lakes. For example, zooplanktivory occurred in the same lakes as consumption from offshore habitats; piscivory occurred in the same lakes as consumption from littoral benthic habitats. Redundancy analyses (RDA) were used to investigate how lake environment was related to consumption of different prey categories. The RDA indicated that piscivory exhibited by Arctic charr was reduced where brown trout were abundant and lakes were shallow, greater zooplanktivory occurred at lower latitudes and under decreased nutrient but higher silicon dioxide concentrations, and benthic resource consumption was associated with shallower lakes and higher altitudes. This study showed that trends previously observed across fish species were supported at the intraspecific level, indicating that a single species with flexible dietary habits can fill functional roles expected of multiple species in more diverse food webs.

Trends in marine climate change research in the Nordic region since the first IPCC report

Oceans are exposed to anthropogenic climate change shifting marine systems toward potential instabilities. The physical, biological and social implications of such shifts can be assessed within individual scientific disciplines, but can only be fully understood by combining knowledge and expertise across disciplines. For climate change related problems these research directions have been well-established since the publication of the first IPCC report in 1990, however it is not well-documented to what extent these directions are reflected in published research. Focusing on the Nordic region, we evaluated the development of climate change related marine science by quantifying trends in number of publications, disciplinarity, and scientific focus of 1362 research articles published between 1990 and 2011. Our analysis showed a faster increase in publications within climate change related marine science than in general marine science indicating a growing prioritisation of research with a climate change focus. The composition of scientific disciplines producing climate change related publications, which initially was dominated by physical sciences, shifted toward a distribution with almost even representation of physical and biological sciences with social sciences constituting a minor constant proportion. These trends suggest that the predominantly model-based directions of the IPCC have favoured the more quantitatively oriented natural sciences rather than the qualitative traditions of social sciences. In addition, despite being an often declared prerequisite to successful climate science, we found surprisingly limited progress in implementing interdisciplinary research indicating that further initiatives nurturing scientific interactions are required.

Evaluating the effectiveness of real-time closures for reducing susceptibility of small fish to capture

Evaluating the effectiveness of real-time closures for reducing susceptibility of small fish to capture Pamela J. Woods*, Bjarki þ or Elvarsson, Thorsteinn Sigurdsson, and Gunnar Stef ansson Science Institute, University of Iceland, Dunhagi 5, 107 Reykjavik, Iceland Marine and Freshwater Research Institute, Sk ulagata 4, 101 Reykjavik, Iceland School of Engineering and Natural Sciences, University of Iceland, Dunhagi 5, 107 Reykjavik, Iceland *Corresponding author: tel: þ354 575 2000; fax: þ354 575 2001; e-mail: pamelajwoods@gmail.com.

Geographic variation in lower pharyngeal jaw morphology in the Shiner Perch Cymatogaster aggregata (Embiotocidae, Teleostei)

Correlations of feeding morphology with body morphology reflect ecological variation of a species and the geographic or ontogenetic scales over which it occurs. In this study, evidence was found for geographic variation in lower pharyngeal jaw (LPJ) morphology of Cymatogaster aggregata Gibbons (Embiotocidae, Teleostei) in the Pacific Northwest, U.S.A. Correlations of LPJ morphology with body morphology were more obvious in adulthood than the juvenile stage. Morphological patterns corresponded better with environmental variables and gut contents than geographic proximity, indicating that they were most likely caused by habitat differences. Qualitative common garden experiments indicated the nature and direction of plastic responses, and indicate a likely plastic origin to most naturally observed differences. Recognizing ecological patterns via morphology is an important first step in understanding how and when ecological mechanisms influence the functional role of an organism within its environment.