Science Applications Forum Enhancing fisheries education through the Canadian Fisheries Research Network: a student perspective on interdisciplinarity, collaboration and 4 inclusivity 5 6

Abstract 31 Fisheries sciences and management involve complex problems not easily addressed by a single 32 set of stakeholders or methodologies from one discipline; accordingly, the Canadian Fisheries 33 Research Network (CFRN) was initiated to increase fisheries research capacity in Canada 34 through interdisciplinary and inclusive research collaborations. We compared the value of the 35 CFRN students' learning experience to that offered in traditional fisheries programs at Canadian 36 universities in training post-graduate students to tackle complex fisheries problems. This paper 37 presents 1) a review of the current state of fisheries education across Canada and 2) reflections 38 on our training within the CFRN, and challenges to implementing its innovative approach to 39 fisheries education. We found few dedicated fisheries programs in Canada and concluded that 40 fisheries research typically relies on securing a supervisor with an interest in fisheries. In 41 contrast, the CFRN enhanced our university training through interdisciplinary and inclusive 42 research collaborations, and by exposure to the realities of industry, government and academics 43 collaborating for sustainable fisheries. We propose a new approach to post-graduate level 44 fisheries education, one that combines interdisciplinarity, collaboration, and inclusivity to 45 produce more capable fisheries scientists and managers. Furthermore, we made 46 recommendations on how universities, researchers, and funding agencies can successfully 47 incorporate these themes into fisheries education. 4

Shelters and Their Use by Fishes on Fringing Coral Reefs

Coral reef fish density and species richness are often higher at sites with more structural complexity. This association may be due to greater availability of shelters, but surprisingly little is known about the size and density of shelters and their use by coral reef fishes. We quantified shelter availability and use by fishes for the first time on a Caribbean coral reef by counting all holes and overhangs with a minimum entrance diameter ≥3 cm in 30 quadrats (25 m2) on two fringing reefs in Barbados. Shelter size was highly variable, ranging from 42 cm3 to over 4,000,000 cm3, with many more small than large shelters. On average, there were 3.8 shelters m−2, with a median volume of 1,200 cm3 and a total volume of 52,000 cm3m−2. The number of fish per occupied shelter ranged from 1 to 35 individual fishes belonging to 66 species, with a median of 1. The proportion of shelters occupied and the number of occupants increased strongly with shelter size. Shelter density and total volume increased with substrate complexity, and this relationship varied among reef zones. The density of shelter-using fish was much more strongly predicted by shelter density and median size than by substrate complexity and increased linearly with shelter density, indicating that shelter availability is a limiting resource for some coral reef fishes. The results demonstrate the importance of large shelters for fish density and support the hypothesis that structural complexity is associated with fish abundance, at least in part, due to its association with shelter availability. This information can help identify critical habitat for coral reef fishes, predict the effects of reductions in structural complexity of natural reefs and improve the design of artificial reefs

Home range relocation: How habitat quality, landscape connectivity and density affect movements in coral reef fish

Short-term immigration via home range relocation has important implications for metapopulation dynamics, sustainable harvest and pest control strategies, and conservation in populations experiencing high localized mortality. Despite its importance, no suitable theory is available to predict immigration in response to harvest near an adjacent protected area. There is also little information about the factors that influence the magnitude of immigration. I developed a compensatory immigration model to predict the effect of harvesting on immigration under different assumptions about the factors limiting immigration. The model predicts that immigration from protected areas can contribute importantly to total yield and population recovery in the harvest area and can strongly affect demography in the protected area. Immigration and total yield can show complex non-linear relationships with harvesting as the size of the protected area, initial rate of replacement, mobility and behavioral interactions vary. I carried out field experiments to validate the model and assess the relative influence of limiting factors to immigration (i.e. population size in the protected area, the relative habitat quality and functional connectivity between the harvest and protected area). I used longfin (Stegastes dienaceus) and dusky damselfish (S. adustus) as a model system. I first examined functional connectivity by translocating damselfish to investigate which habitat or social features represent a barrier to movement during homing. Small sand gaps constitute a partial barrier to movement, but the effect of sand gap width varies with reef configuration, and fish minimize travel over conspecific territories. I carried out replicated, experimental, incremental reduction of damselfish populations to examine the mechanisms behind home range relocation at the scale of the territory and to evaluate immigration at the landscape scale. At the territory scale, the probability that a territory would be recolonized decreases with local density. Territories tend to be reoccupied by individuals of the same species, sex and size as the original occupant, but territories occupied by larger individuals are more likely to be recolonized. At the landscape scale, models assuming a constant but partial replacement of removed individuals predict immigration much better than models that include either no replacement or complete replacement. In several sites, the best fitting model also included parameters describing density dependence that changed in direction and magnitude with cumulative harvest. Total yield and the proportion of removed individuals replaced by immigrants were correlated with the combined effects of relative habitat quality and connectivity of replicate sites. Overall, my thesis proposes and tests a new compensatory immigration model to predict immigration from protected to harvested areas and suggests that variation in mobility, habitat quality, functional connectivity and behavioral interactions must be considered when predicting the effects of immigration in a harvesting context on metapopulation dynamics, sustainable harvest and conservation.Dans les populations qui sont soumises à une forte mortalité locale, l'immigration à court terme - via la relocalisation du domaine vital - a d'importantes implications pour la dynamique des métapopulations, l'exploitation soutenable des ressources, la lutte contre les espèces introduites et invasives et la conservation. Malgré son importance, il n'existe pas de théorie prédisant l'immigration dans une zone exploitée à partir d'une zone protégée adjacente. Il existe aussi très peu d'information sur les facteurs influençant l'intensité de l'immigration. J'ai développé un modèle d'immigration compensatoire afin de prédire les effets d'une réduction locale de la densité sur l'immigration en utilisant des scénarios hypothétiques variant dans l'inclusion de facteurs limitant. Le modèle prédit que l'immigration peut contribuer à la récolte totale et à la récupération des populations exploitées et peut affecter la démographie dans la zone protégée. L'immigration et la récolte totale sont reliées de façon complexe et non-linéaire avec l'exploitation cumulative en relation avec la taille de l'aire protégée, le taux initial de remplacement des individus récoltés, la mobilité et les interactions comportementales. Des expériences sur le terrain m'ont permis de valider le modèle et d'estimer l'influence relative de facteurs limitant à l'immigration (i.e. la taille de la population dans la zone protégée, la qualité de l'habitat relative et la connectivité fonctionnelle entre la zone exploitée et la zone protégée). J'ai utilisé la demoiselle noire (Stegastes dienaceus) et la demoiselle brune (S. adustus) et leur habitat comme système modèle. J'ai examiné en premier lieu la connectivité fonctionnelle en relocalisant des demoiselles afin d'investiguer quelles caractéristiques de l'habitat ou caractéristiques sociales peuvent représenter une barrière au mouvement lors du comportement de retour au territoire (ang. « homing »). Les petites étendues de sable constituent une barrière partielle au mouvement mais l'effet de la taille de l'étendue de sable varie en fonction de la configuration des récifs. Les poissons minimisent les mouvements au-dessus des territoires de leur conspécifiques. J'ai également entrepris une réduction expérimentale, incrémentée et répliquée de populations de demoiselles qui a servi à examiner les mécanismes régissant la relocalisation du domaine vital à l'échelle du territoire et l'immigration à l'échelle du paysage. À l'échelle du territoire, la probabilité qu'un territoire soit recolonisé diminue avec une réduction de la densité. Les territoires ont tendance à être recolonisés par des individus de la même espèce, du même sexe et de taille comparable à celle de l'occupant original. Les territoires occupés initialement par les individus les plus gros ont une probabilité plus forte d'être recolonisés. À l'échelle du paysage, les modèles qui assument un remplacement constant mais partiel des individus récoltés ont un meilleur support statistique que les modèles incluant soit un remplacement incomplet ou une absence de remplacement. Dans plusieurs sites où la densité à été manipulée, le modèle ayant le meilleur support statistique incluait également des paramètres modélisant de la densité dépendance (i.e. changement de direction et d'intensité en relation avec la récolte cumulative). La récolte totale et la proportion des individus récoltés qui étaient remplacés par les immigrants étaient corrélées avec l'effet combiné de la qualité de l'habitat et de la connectivité fonctionnelle. En conclusion, ma thèse propose et test un modèle d'immigration compensatoire prédisant l'immigration d'individus habitant les aires protégées vers les zones exploitées. Ce modèle considère la variation de la mobilité, la qualité de l'habitat, la connectivité fonctionnelle et les interactions comportementales afin de prédire les effets de l'immigration dans un contexte d'exploitation soutenable et de conservation à l'échelle de la métapopulation

DATA - Immigration rate in relation to density

*Immigration data in response to a localized and experimental removal of two related damselfish species (<i>Stegastes diencaeus </i>and <i>S. adustus</i>). This dataset contains 12 columns.  Data were collected in Barbados between 2005 and 2007 during summer.<br> <p>Column 1; SITES: site in witch the experiment was performed. <br></p><p>Column 2;  DATE_REMOVAL: Date at which the removal event was performed<br></p><p>Column3; REMOVAL: Sequential Removal event (0 = before the density manipulation).</p> <p>Column 4: DENSITY: Damselfish density on the site AFTER a given removal event. If REMOVAL = 0, no damselfish was removed so the number represents the initial population size<br></p><p>Column 5: NUMBER_HARVESTED_FISH: The number of harvested individual per removal event</p><p>Column 6: IMMIGRANTS_PER_REMOVAL: The number of immigrants after a given removal event</p> <p>Column 7: IMMIGRANTS_PER_NEW_VACANCY: The number of immigrants per new vacancy created. Immigrants/vacancy; where vacancy = (DENSITY t-1)-(DENSITYt)<br></p> <p>Column 8: IMMIGRANTS_PER_RESIDENT: Per capita immigration rate. IMMIGRANTS/DENSITY</p><p>Column 9: HARVESTED_STDI: Number of harvested <i>Stegastes diencaeus</i> (Longfin damselfish)<br></p><p>Column 10: HARVESTED_STAD Number of harvested <i>Stegastes adustus</i> (Dusky damselfish)</p><p>Column 11: IMMIGRANTS_STDI Number of immigrants <i>Stegastes diencaeus</i> (Longfin damselfish)</p><p>Column 12: IMMIGRANTS_STAD: Number of immigrants <i>Stegastes adustus</i> (Dusky damselfish)</p><p><br></p><p><br></p> <p> </p

Boreal river impoundments caused nearshore fish community assemblage shifts but little change in diversity: A multi-scale analysis

River flow regulation, fragmentation and changes in water quality caused by dams have varying effects on aquatic biodiversity and ecosystem functions, but are not clearly resolved in boreal ecosystems. We adopted a multi-scale approach to quantify fish community trajectories over 20 years using a network of sites spread across four reservoirs in two hydroelectricity complexes in northern QuĂŠbec, where other anthropogenic factors have been negligible. Across three spatial scales, we found little evidence of directional temporal trends in diversity relative to reference sites. Using beta-diversity analyses, we also detected a high degree of stability in fish composition over time and space at the complex and reservoir scales. However, changes in species assemblage following impoundment were detected at the scale of the sampling station. At this scale, we found that some species consistently benefited (coregonids and pikes) from impoundment whereas others were detrimentally affected (suckers and one salmonid). Overall, we conclude that examining different scales is key when trying to understand the impacts of humans on biodiversity and in formulating management recommendations.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Immigration Rates during Population Density Reduction in a Coral Reef Fish

<div><p>Although the importance of density-dependent dispersal has been recognized in theory, few empirical studies have examined how immigration changes over a wide range of densities. In a replicated experiment using a novel approach allowing within-site comparison, we examined changes in immigration rate following the gradual removal of territorial damselfish from a limited area within a much larger patch of continuous habitat. In all sites, immigration occurred at intermediate densities but did not occur before the start of removals and only rarely as density approached zero. In the combined data and in 5 of 7 sites, the number of immigrants was a hump-shaped function of density. This is the first experimental evidence for hump-shaped, density-dependent immigration. This pattern may be more widespread than previously recognized because studies over more limited density ranges have identified positive density dependence at low densities and negative density dependence at high densities. Positive density dependence at low density can arise from limits to the number of potential immigrants and from behavioral preferences for settling near conspecifics. Negative density dependence at high density can arise from competition for resources, especially high quality territories. The potential for non-linear effects of local density on immigration needs to be recognized for robust predictions of conservation reserve function, harvest impacts, pest control, and the dynamics of fragmented populations.</p></div

AICc scores (AICc) and Akaike weights (w_<i>i</i>) for each of the six empirical functions predicting the observed number of immigrants arriving on the site following a removal event in relation to population size of damselfish following that removal event (site scaling) on seven experimental sites.

<p>For each site, the function with the highest support is indicated by bold fonts for the AICc and w_<i>i</i>. Sites are ordered as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0156417#pone.0156417.g001" target="_blank">Fig 1</a>. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0156417#pone.0156417.g001" target="_blank">Fig 1</a> for site abbreviations and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0156417#pone.0156417.t001" target="_blank">Table 1</a> for the functions.</p