We investigated the association between maternal expressed emotion and twin relationship quality, after controlling for a maternal questionnaire measure of the mother–child relationship. This was explored within a community sample of 156 mothers and their two young twin children (Mchild age = 3.69 years; SDchild age = 0.37). Mothers reported on the twin–twin relationship and the mother–child relationship via questionnaire. They were also interviewed about each child using the innovative Preschool Five Minute Speech Sample (Daley et al., 2003), which yields information about relative positive:negative maternal expressed emotion. Mothers who expressed more family-wide positive emotion and less family-wide negative emotion also reported more positivity, but not negativity, within the twin relationship — even when controlling for questionnaire reports of the mother–child relationship. Counter to expectations, discrepancies in mothers’ expressed emotion between their twins also predicted more positive sibling relationships. Our findings corroborate the well established spill-over effect, whereby families are viewed as emotional units of interdependent individuals, none of whom can be understood in isolation from one another. Most importantly, the Preschool Five Minute Speech Sample provides information about mothering that questionnaire reports may not, and thus it is a useful tool in better understanding the twin family system.

As marine protected areas (MPAs) are increasingly being utilised as a tool for fisherymanagement, their impact on the food web needs to be fully understood. However, little isknown about the effect of MPAs on fish assemblages, especially in the presence ofdifferent life history and ecological traits. Modelling the observed changes in fishpopulation structures may provide a mechanistic understanding of fish assemblage dynamics.In addition, modelling allows a quantitative estimate of MPA spill-over. To achieve thispurpose, we adapted an existing ecosystem model, OSMOSE (Object-oriented simulator ofmarine biodiversity exploitation), to the specific case of the presence of fish withmultiple life histories. The adapted model can manage 4 main categories of life historyidentified in an estuary MPA: fish that (1) spend their entire life cycle locally, (2) arepresent only as juveniles, (3) enter the area as juveniles and stay permanently exceptduring reproduction periods, which occur outside the estuary, and (4) are presentoccasionally and for a short time for foraging purposes. To take into account thesespecific life-history traits, the OSMOSE code was modified. This modelling approach wasdeveloped in the context of the Bamboung Bolong MPA, located in a mangrove area in theSine-Saloum Delta, Senegal. This was the ideal case to develop our approach as there hasbeen scientific monitoring of the fish population structure inside the MPA before fisheryclosure, providing a reference state, and continuous monitoring since the closure.Ecologically similar species were pooled by trophic traits into 15 groups that represented97% of the total biomass. Lower trophic levels (LTL) were represented by 6 compartments.The biomass of the model species was calibrated to reproduce the reference situationbefore fishery closure. Model predictions of fish assemblage changes after fishery closurecorresponding to the Bamboung MPA creation scenario were compared to field observations;in most cases the model reproduces observed changes in biomass (at least in direction). Wesuggest the existence of a “sanctuary effect”, that was not taken into account in themodel, this could explain the observed increase in biomass of top predators not reproducedby the model. Finally, the annual MPA fish spill-over was estimated at 11 tons (~33% ofthe fish biomass) from the model output, mainly due to diffusive effects.

New Zealand fur seals in the New Zealand area are increasing in number following earlier depletion by Polynesians and Europeans. Otago Peninsula, South Island is a region where recent re-colonization has occurred. We identified 27 breeding and 41 non-breeding colonies in 1998. At higher densities the shortage of space in breeding colonies may initiate emigration by first-time breeders to suitable sites nearby. This hypothesis assumes philopatry (repeated return to a natal site) and site fidelity (repeated return to a non-natal site). We quantified the rate of increase in pup production at Otago Peninsula since the early 1980s using annual counts of fur seals ashore from 1994 to 1998 and data on pup numbers before 1994 from the literature. The exponential rate of increase (b) ranged from 0.22 to 0.30 (95% confidence interval) and the average (arithmetic) rate of annual increase (r) was 0.30. To search for evidence of philopatry, site fidelity and immigration, relationships between counts of pups established colonies in 1996–1998 were measured and found to be highly correlated. We then tested whether new breeding colonies were established nearer to existing breeding colonies than would be expected by chance. There was significant spatial clustering of new breeding colonies around the 6 focal (established) colonies. We found no evidence for an association between the appearance of new colonies and r at nearby established colonies. Increasing numbers of fur seals on Otago Peninsula have resulted in the rapid proliferation of colonies, and their clustering is indicative of a ‘spill-over’ effect where young individuals choose to breed near to established breeders.