Hólar University College

ABSTRACT Feed costs and limited knowledge of feeding strategies are a major constraint to the sustainability of semi‐intensive Nile tilapia aquaculture systems in sub‐Saharan Africa. In semi‐intensive systems, Nile tilapia ( Oreochromis niloticus ) utilizes natural pond production and supplemental feed, but their relative contributions to growth remain unclear. A 90‐day pond experiment assessed the effects of feeding regimes on Nile tilapia trophic dynamics and growth. Fingerlings (5.6 ± 0.14 g) were stocked at 3 fish m −2 in 15 ponds and assigned to five treatments: low (1%), medium (2%) and high (4%) feeding under standard fertilization and two double‐fertilized treatments with continuous low feeding (DF/L) or delayed feeding (DF/2N/1M; no feed for 60 days, then 2% for 30 days). Diet composition was assessed using δ 1 3 C and δ 1 5 N mixing models. Growth did not differ among treatments in the first 2 months but diverged in the last month. Delayed feeding combined with fertilization (DF/2N/1M) resulted in superior growth performance, efficient feed utilization and limited physiological stress compared to continuous feeding. Stable isotope analysis showed that fish in M, DF/L and DF/2N/1M fed mainly on zooplankton with limited detectable feed assimilation based on endpoint muscle isotope signatures. H fish consumed mostly sediment organic matter, whereas L fish had a mixed diet of feed, zooplankton, zoobenthos and sediment. These findings align with earlier stomach content studies showing tilapia <80–100 g rely primarily on secondary pond production rather than feed, though isotopic lag may have masked late feed uptake. These findings demonstrate that optimized feeding strategies can enhance productivity while reducing feed inputs, thereby improving the sustainability of semi‐intensive Nile tilapia aquaculture in East Africa.

<title>Abstract</title> Fecundity selection is widely invoked to explain female-biased sexual size-dimorphism (SSD), yet tests based on lifetime reproductive output remain scarce. We quantified lifetime fecundity and age-dependent reproduction in the size-dimorphic spider <italic>Nephilingis cruentata</italic> , in which mating plugs restrict females to sperm from one/two copulations. We found no support for ongoing fecundity selection. Female body mass was positively associated with mean mass of viable egg-sacs but negatively with their number, so that total viable egg-sac mass did not increase with body size. Furthermore, maternal size effects on offspring survival were sex-specific: sons of larger females less likely reached maturity, whereas daughters were unaffected. Reproductive trajectories featured production of several viable egg-sacs followed by a terminal phase of non-viable egg-sacs. This pattern, and a decline in egg-sac viability with time since mating, support sperm depletion/deterioration as the primary constraint on fecundity, with weak evidence for reproductive senescence and none for adaptive restraint or terminal investment. Females that copulated twice showed no fecundity advantage but had shorter lifespans. We show that larger females do not achieve higher lifetime reproductive success and that sperm limitation may erase fecundity advantages of large female, questioning the generality of fecundity selection as a driver of female-biased SSD.

Tourism in rural areas is widely believed to be the white horse carrying the proverbial knight on a rescue mission. That is the new industry that can bring prosperity to communities where traditional resource extraction and/and or manufacturing industries have declined. Such perceived positive economic impacts are identified in the tourism literature as important for residents' positive attitudes toward tourism development (Sharpley, 2014). However attitudes toward tourism are complex and contingent upon various factors in resident's quality of life (Kim, Uysal &amp; Sirgy, 2013; Andereck &amp; Nyaupane, 2011), social and cultural sustainability (Birkeland &amp; Brunt &amp; Courtney, 1999I. It is also important to define more precisely what is taken as sustainable in tourism (Buckley, 2012; Saarinen, 2006). While research on tourism impacts commonly focusses on negative impacts and carrying capacity in popular destinations, it is important to take into the knowledge account destinations at various stages in their development (Canavan, 2014; Kim, Uysal &amp; Sirgy, 2013) and to acknowledge that research into social and cultural sustainabity needs more attention. Drawing upon data from a study of rural tourism in Iceland and Norway, we argue that the concept of destination clouds the discourse on tourism impacts in rural areas. Tourism may have underestimated impacts as the dark rental horse trotting through town.

ABSTRACT High feed costs constrain tilapia production, making exploring low‐cost feeding strategies important. We assessed the growth of tilapia over a period of 6 months, fed 1%, 2%, or 4% of body mass day −1 with and without fertilization in 18 liner ponds stocked with fingerlings (5.1 ± 0.71 g). Growth was significantly better in fertilized ponds than in unfertilized ponds. The best growth (320.7 ± 8.5 g) was in fertilized ponds where fish were fed 2%, achieving a 45% larger weight gain than in the group fed 4% in unfertilized ponds. These results show that with fertilization, the feeding can be reduced by half while still having better growth than in unfertilized ponds. In fertilized ponds fed 4%, the minimum nocturnal oxygen levels may have limited growth of the fish and, as a result, their final weight (180.1 ± 6.6 g) was lower than in groups fed 2% in fertilized ponds and 4% in unfertilized ponds. Fish up to 60–90 g rely mainly on zooplankton as a source of food, while fish of sizes ≥100 g rely mainly on supplementary feed. Analysis of the gut content of fish of different sizes suggested that tilapia up to 60–90 g do not consume the feed presented which instead ends up as an expensive form of fertilizer. The best economic return was in ponds that were fertilized and fed 2%. It is concluded that feed‐use and production costs may be reduced even further by fertilizing the ponds and restricting or omitting feeding of fish &lt; 100 g and only commence feeding when the fish have reached around 100 g. The results of the finding have a wider applicability in developing countries where pond culture of tilapia is common.

PurposeThe purpose of this conceptual paper is to explore the potential of regenerative tourism practices and their influence on destinations and their stakeholders from a community development approach focusing on Nordic lifestyle entrepreneurs. We focus on small and micro-sized enterprises (SMiEs) that conform to the realities of tourism systems in Nordic regions.Design/methodology/approachWe explore how community development can be used as an approach for regenerative tourism and vice versa. Our conceptual paper builds from recent work of the Nordic Regenerative Tourism project, which aims to develop place-based practices for SMiEs that contribute to the regeneration of natural and cultural resources.FindingsRegenerative tourism research should focus on developing tools that aid in capacity sharing and equitable partnerships through a community development approach. However, there is a lack of understanding of the processes of how to implement this in real world practice. More research is needed in developing tools to mobilize Nordic communities, particularly within the countryside to help transform tourism towards a regenerative model. It was found that much of these efforts comes from MSMEs. Therefore, more case studies are needed to understand how and why lifestyle entrepreneurs play in community revitalization efforts and the potential linkages with regenerative tourism management and marketing.Originality/valueThis conceptual paper contributes to the discussion of regenerative tourism and focus on smaller countryside communities within the Nordics. We argue that community development is linked with the concept of regenerative tourism through lifestyle entrepreneurs.

ABSTRACT Low quality feeds are an impediment to sustainable fish farming in East Africa. Low quality feeds affect fish growth, pollute the aquatic ecosystem, escalate conflicts among competing water resource users, and affect enterprise sustainability. We investigated the physical and nutrient attributes, and the aflatoxin levels of selected fish feeds in E. Africa. The actual crude protein and crude lipid of the feeds deviated from the package quoted values by −20 to 7% and −5.5 to 9.6%, respectively. All feeds were inadequate in essential minerals, and their aflatoxin levels were low (range: 8.71 ± 0.52 to 71.90 ± 0.59 µg/kg). We highlight the potential effects of using low-quality feeds on the fed fish, aquatic ecosystem, and aquaculture sustainability in East Africa. To ensure a healthy aquatic environment with reduced resource-use conflicts and sustainable fish farming, ambitious policy reviews are recommended.

ABSTRACTAs aquaculture intensifies, maintaining conducive conditions for sustainable production becomes a key priority. The expansion in farm number and perfarm production puts pressure on the environment and increases susceptibility of the cultured fish to disease, leading to production loss by the investors. This study was conducted in cage aquaculture systems located in three riparian counties in Lake Victoria, Kenya to investigate the combined role of biosecurity and adherence to best management practices (BMPs) by looking at the knowledge, attitude, and practices (KAP) of the cage aquaculture farmers. Additionally, it examined the link between biosecurity, BMPs, and water quality in the context of promoting fish health and preventing fish kills in the cage aquaculture of Nile tilapia in Lake Victoria, Kenya. Gulf and open water locations were included in the study design. A semi‐structured questionnaire was used to gather qualitative information on the KAP of fish farmers to biosecurity and BMPs in the cage aquaculture farms. For water quality analysis, quantitative data was utilised. Results showed that the farmers had a positive attitude towards various biosecurity and BMP concepts and a moderate level of knowledge, but the practices on the farm were not in concurrence with both their attitudes and knowledge. Using a customised aquaculture performance index score, which assessed compliance to some BMPs and biosecurity, only 8% of the farms under investigation had a good score, while 24% had an average score and the majority (68%) had a poor score. Additionally, a good aquaculture performance index score was inversely related to ammonia levels. This finding suggests the need to locate cage fish farms in areas with better water circulation. The study highlights the need for capacity building on the importance of adherence to biosecurity and BMPs in the cage aquaculture of Nile tilapia in the lake for enhanced productivity and sustainability of the lake ecosystem.

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