Survival and behaviour of juvenile red rock lobster, Jasus edwardsii, on rocky reefs with varying predation pressure and habitat complexity

2008 ◽  
Vol 59 (3) ◽  
pp. 246 ◽  
Author(s):  
K. A. S. Mislan ◽  
Russ C. Babcock
Keyword(s):  
New Zealand ◽  
Kelp Forest ◽  
Predatory Fish ◽  
Rocky Reef ◽  
Rocky Reefs ◽  
Jasus Edwardsii ◽  
Fish Predators ◽  
Two Factors ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts

The role of large predatory fish in coastal communities is generally unknown because of overfishing. In order to understand the direct and indirect impacts of these increased population sizes on coastal food chains, the effect of areas with more fish predators on the survival and behaviour of potential prey was assessed. Juvenile lobsters, Jasus edwardsii (10–20 mm carapace length), were tethered on rocky reefs inside and outside marine reserves in northeastern New Zealand to assess survival under differing predator densities. Since rocky reef habitats in northeastern New Zealand include zones of kelp forest and barren reef, a two-way factorial design was used to determine the effects of predators, habitat, and the interaction of these two factors on juvenile lobster survival. Overall, the results indicated that neither varying large fish density nor varying kelp density had direct impacts on the survival rate of juvenile lobsters. Laboratory manipulations demonstrated behavioural changes by juvenile lobsters such that when a large predatory fish was present, juvenile lobsters spent significantly less time moving, even when separated from the predator by a porous barrier. Thus areas with more fish predators may increase juvenile lobster survival but potentially at the cost of reduced feeding opportunities.

scholarly journals Population Genetics of the Red Rock Lobster,  Jasus edwardsii

2021 ◽  
Author(s):  
◽  
Luke Thomas
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
New Zealand ◽  
Genetic Differentiation ◽  
Microsatellite Markers ◽  
Rocky Reef ◽  
Rock Lobster ◽  
Wide Range ◽  
Jasus Edwardsii ◽  
Polymorphic Microsatellite

<p>Understanding patterns of gene flow across a species range is a vital component of an effective fisheries management strategy. The advent of highly polymorphic microsatellite markers has facilitated the detection of fine-scale patterns of genetic differentiation at levels below the resolving power of earlier techniques. This has triggered the wide-spread re-examination of population structure for a number of commercially targeted species. The aims of thesis were to re-investigate patterns of gene flow of the red rock lobster Jasus edwardsii throughout New Zealand and across the Tasman Sea using novel microsatellite markers. Jasus edwardsii is a keystone species of subtidal rocky reef system and supports lucrative export markets in both Australia and New Zealand. Eight highly polymorphic microsatellite markers were developed from 454 sequence data and screened across a Wellington south coast population to obtain basic diversity indices. All loci were polymorphic with the number of alleles per locus ranging from 6-39. Observed and expected heterozygosity ranged from 0.563-0.937 and 0.583-0.961, respectively. There were no significant deviations from Hardy-Weinberg equilibrium following standard Bonferroni corrections. The loci were used in a population analysis of J. edwardsii that spanned 10 degrees of latitude and stretched 3,500 km across the South Pacific. The analysis rejected the null-hypothesis of panmixia based on earlier mDNA analysis and revealed significant population structure (FST=0.011, RST=0.028) at a wide range of scales. Stewart Island was determined to have the highest levels of genetic differentiation of all populations sampled suggesting a high degree of reproductive isolation and self-recruitment. This study also identified high levels of asymmetric gene flow from Australia to New Zealand indicating a historical source-sink relationship between the two countries. Results from the genetic analysis were consistent with results from oceanographic dispersal models and it is likely that the genetic results reflect historical and contemporary patterns of Jasus edwardsii dispersal and recruitment throughout its range.</p>

Mass mortality of a dominant kelp (Laminariales) at Goat Island, north-eastern New Zealand

1996 ◽  
Vol 47 (7) ◽  
pp. 907 ◽  
Author(s):  
RG Cole ◽  
RC Babcock
Keyword(s):  
New Zealand ◽  
Marine Reserve ◽  
Kelp Forest ◽  
Austral Summer ◽  
Mass Mortality ◽  
Ecklonia Radiata ◽  
Rocky Reefs ◽  
North Eastern ◽  
Mass Mortalities

In north-eastern New Zealand, monospecific stands of the laminarian Ecklonia radiata occupy rocky reefs at depths below 10 m on exposed shores. In the austral summer of 1992-93, mass mortalities of populations of E. radiata in the Cape Rodney to Okakari Point Marine Reserve near Leigh were recorded, in which 40-100% of the sporophytes at depths greater than 10 m died. Mortality was gradual, beginning with erosion of the laminae and ultimately progressing to the stipes, which eventually decayed. The mortality was first evident in the deepest plants and culminated in the elimination of large areas of kelp forest. The event was not associated with any previously reported mortality agents. Investigations of the effects of the mortality on other organisms are continuing.

Spatiotemporal variation in the structure of reef fish and macroalgal assemblages in a north-east Atlantic kelp forest ecosystem: implications for the management of temperate rocky reefs

2018 ◽  
Vol 69 (4) ◽  
pp. 525 ◽  
Author(s):  
Pablo Pita ◽  
Diana Fernández-Márquez ◽  
Juan Freire
Keyword(s):  
Reef Fish ◽  
Fish Assemblages ◽  
Kelp Forest ◽  
Habitat Destruction ◽  
Kelp Forests ◽  
Rocky Reef ◽  
Laminaria Hyperborea ◽  
East Atlantic ◽  
North East ◽  
Rocky Reefs

Temperate rocky reefs and kelp forest ecosystems have been severely affected by overfishing, pollution and habitat destruction, and climate change is a major driver of kelp decline in many regions. Although necessary for management, ecological interactions between kelp and fish remain largely unknown in the north-east Atlantic. In the present study, underwater visual censuses (UVC) and univariate and multivariate multiple regression models were used to analyse the spatiotemporal variations in the abundance and habitat use of the rocky reef fish and macroalgae assemblages of Galicia (north-west Spain). The underwater seascape was dominated by large rocks and kelp forests of Laminaria hyperborea, L. ochroleuca and Saccorhiza polyschides. Fish assemblages were ruled by gadids, labrids and sparids. The most frequent fish species were Labrus bergylta (counted in 90% of UVC) and Pollachius pollachius (in 100% of UVC), whereas the most abundant were Boops boops (mean±s.d., 556.4±39.7 individuals ha–1) and L. bergylta (432.10±440.05 individuals ha–1). Fish and macroalgal assemblages showed different spatial preferences and responded strongly to seasonality, wave exposure and depth. To a lesser degree, fish and macroalgal assemblages showed preferences for habitat structure. Moreover, because the findings of the present study indicate that L. bergylta is a good indicator species of the health of rocky reef and kelp forests ecosystems, monitoring of this fish can be helpful for management and conservation actions.

scholarly journals The sea urchin – the ultimate herbivore and biogeographic variability in its ability to deforest kelp ecosystems

2013 ◽  
Author(s):  
Jarrett E Byrnes ◽  
Ladd E. Johnson ◽  
Sean D. Connell ◽  
Nick T. Shears ◽  
Selena M McMillan ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Large Scale ◽  
Sea Urchins ◽  
Meta Analysis ◽  
Kelp Forest ◽  
Rocky Reef ◽  
Rocky Reefs ◽  
Iconic Images ◽  
Balance Of Forces ◽  
Almost All

Barren rocky seafloor landscapes, denuded of almost all life by ravenous sea urchins, liberated from their predators, stands as one of the iconic images of trophic cascades in Ecology. While this paradigm has been cited in nearly every temperate rocky reef ecosystem across the globe, there is widespread disagreement as to its generality. Given their biology, sea urchins are clearly one of the ocean’s strongest herbivores in many systems, but where will their impact be strongest? Here we perform a global meta-analysis of sea urchin-kelp relationships in the field. We find that sea urchins appear to be able to control kelp abundances in any system where they can achieve high densities. Furthermore, their ability to create large-scale long-lasting barrens appears to be limited to biogeographic regions where they can achieve high consumptive potential. Based on the literature, we outline a conceptual model that examines when and where sea urchins should be able to have a strong regulating impact on kelp forest ecosystems. We suggest that many elements of global change may shift the balance of forces regulating sea urchin consumptive potential in these ecosystems. Given their ability to have strong impacts on temperate rocky reefs, these drivers need to be considered in concert with their effect on sea urchins when attempting to predict future change to marine ecosystems.

scholarly journals The sea urchin – the ultimate herbivore and biogeographic variability in its ability to deforest kelp ecosystems

2013 ◽  
Author(s):  
Jarrett E Byrnes ◽  
Ladd E. Johnson ◽  
Sean D. Connell ◽  
Nick T. Shears ◽  
Selena M McMillan ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Large Scale ◽  
Sea Urchins ◽  
Meta Analysis ◽  
Kelp Forest ◽  
Rocky Reef ◽  
Rocky Reefs ◽  
Iconic Images ◽  
Balance Of Forces ◽  
Almost All

Barren rocky seafloor landscapes, denuded of almost all life by ravenous sea urchins, liberated from their predators, stands as one of the iconic images of trophic cascades in Ecology. While this paradigm has been cited in nearly every temperate rocky reef ecosystem across the globe, there is widespread disagreement as to its generality. Given their biology, sea urchins are clearly one of the ocean’s strongest herbivores in many systems, but where will their impact be strongest? Here we perform a global meta-analysis of sea urchin-kelp relationships in the field. We find that sea urchins appear to be able to control kelp abundances in any system where they can achieve high densities. Furthermore, their ability to create large-scale long-lasting barrens appears to be limited to biogeographic regions where they can achieve high consumptive potential. Based on the literature, we outline a conceptual model that examines when and where sea urchins should be able to have a strong regulating impact on kelp forest ecosystems. We suggest that many elements of global change may shift the balance of forces regulating sea urchin consumptive potential in these ecosystems. Given their ability to have strong impacts on temperate rocky reefs, these drivers need to be considered in concert with their effect on sea urchins when attempting to predict future change to marine ecosystems.

scholarly journals Population Genetics of the Red Rock Lobster,  Jasus edwardsii

2021 ◽  
Author(s):  
◽  
Luke Thomas
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
New Zealand ◽  
Genetic Differentiation ◽  
Microsatellite Markers ◽  
Rocky Reef ◽  
Rock Lobster ◽  
Wide Range ◽  
Jasus Edwardsii ◽  
Polymorphic Microsatellite

<p>Understanding patterns of gene flow across a species range is a vital component of an effective fisheries management strategy. The advent of highly polymorphic microsatellite markers has facilitated the detection of fine-scale patterns of genetic differentiation at levels below the resolving power of earlier techniques. This has triggered the wide-spread re-examination of population structure for a number of commercially targeted species. The aims of thesis were to re-investigate patterns of gene flow of the red rock lobster Jasus edwardsii throughout New Zealand and across the Tasman Sea using novel microsatellite markers. Jasus edwardsii is a keystone species of subtidal rocky reef system and supports lucrative export markets in both Australia and New Zealand. Eight highly polymorphic microsatellite markers were developed from 454 sequence data and screened across a Wellington south coast population to obtain basic diversity indices. All loci were polymorphic with the number of alleles per locus ranging from 6-39. Observed and expected heterozygosity ranged from 0.563-0.937 and 0.583-0.961, respectively. There were no significant deviations from Hardy-Weinberg equilibrium following standard Bonferroni corrections. The loci were used in a population analysis of J. edwardsii that spanned 10 degrees of latitude and stretched 3,500 km across the South Pacific. The analysis rejected the null-hypothesis of panmixia based on earlier mDNA analysis and revealed significant population structure (FST=0.011, RST=0.028) at a wide range of scales. Stewart Island was determined to have the highest levels of genetic differentiation of all populations sampled suggesting a high degree of reproductive isolation and self-recruitment. This study also identified high levels of asymmetric gene flow from Australia to New Zealand indicating a historical source-sink relationship between the two countries. Results from the genetic analysis were consistent with results from oceanographic dispersal models and it is likely that the genetic results reflect historical and contemporary patterns of Jasus edwardsii dispersal and recruitment throughout its range.</p>

Comparative Study Of Green Practices In Haryana State Universities

Think India ◽  
2019 ◽  
Vol 22 (3) ◽  
pp. 1008-1016
Author(s):  
Priyanka ◽  
Ms Ipshita Bansal
Keyword(s):  
State Universities ◽  
Small Cities ◽  
Large Size ◽  
Green Practices ◽  
Size Population ◽  
Multiple Case ◽  
Multiple Case Studies ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
Complex Activities

Universities in the state are regarded as ‘small cities’ due to their large size, population, and the various complex activities taking place in campuses, which have some serious direct and indirect impacts on the environment. The current study focuses on the green practices in state universities of Haryana. The comparative analysis has been done between the multiple case studies and find out the best green practices being adopted in universities for moving towards making the green campus and recommend the area of improvement for making environment sustainable campus.

scholarly journals Impact of Entrepreneurship Extracurricular Activities and Inspiration on Entrepreneurial Intention: Mediator and Moderator Effect

SAGE Open ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 215824402110321
Author(s):  
Thuy Thu Nguyen ◽  
Linh Thi Phuong Nguyen ◽  
Hoa Thi Thanh Phan ◽  
Anh Trong Vu
Keyword(s):  
Extracurricular Activities ◽  
Structural Equation ◽  
Entrepreneurial Intention ◽  
Equation Modeling ◽  
Moderator Effect ◽  
Technical Students ◽  
Research Findings ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
The Impact

This empirical study proposed a comprehensive model testing the direct and indirect impacts of entrepreneurship extracurricular activities and entrepreneurship inspiration on students’ entrepreneurial intention. With the sample consisting of 640 students from 11 universities in Vietnam, the study used structural equation modeling analysis approach. The results revealed that entrepreneurship extracurricular activities and entrepreneurship inspiration are significantly related to students’ entrepreneurial intention, and entrepreneurship self-efficacy partially mediates these relations. The impact of entrepreneurship education on entrepreneurial intention differs across the field of study. Technical students generally get more benefits from entrepreneurship educational activities than business and economics students do. The research findings recommended some implications for fostering graduates’ entrepreneurship in emerging countries.

scholarly journals Group Facilitation on Societal Disruption and Collapse: Insights from Deep Adaptation

2021 ◽  
Vol 13 (11) ◽  
pp. 6280
Author(s):  
Jem Bendell ◽  
Katie Carr
Keyword(s):  
Climate Change ◽  
Environmental Degradation ◽  
First Person ◽  
Group Facilitation ◽  
Environmental Destruction ◽  
Difficult Conversations ◽  
Radical Uncertainty ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts

This article synthesises the practice and rationale behind ways of facilitating gatherings on topics of societal disruption and collapse, which is argued to be useful for lessening damaging responses. The authors draw on first-person inquiry as facilitators of gatherings, both online and in person, in the post-sustainability field of ‘Deep Adaptation,’ particularly since 2018. This term describes an agenda and framework for people who believe in the probable, inevitable or unfolding collapse of industrial consumer societies, due to the direct and indirect impacts of human-caused climate change and environmental degradation. Some of the principles of Deep Adaptation facilitation are summarised, such as containment, to enable co-responsibility for a safe enough space for difficult conversations. Another key principle is welcoming radical uncertainty in response to the anxieties that people feel from their anticipation of collapse. A third principle is making space for difficult emotions, which are welcomed as a natural and ongoing response to our predicament. A fourth aspect is a curiosity about processes of othering and separation. This paper provides a review of the theories that a reason for environmental destruction is the process of othering people and nature as being less significant or meaningful. One particular modality called Deep Relating is outlined.

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