scholarly journals Ecology of New Zealand Deep-sea Chondrichthyans

2021 ◽  
Author(s):  
◽  
Brit Finucci
Keyword(s):  
Life History ◽  
New Zealand ◽  
Deep Sea ◽  
Life Histories ◽  
Biological Data ◽  
Trawl Survey ◽  
Depth Range ◽  
Ontogenetic Changes ◽  
Adult Females ◽  
The Impact

<p>Deep-sea chondrichthyans represent nearly half of the known species of sharks, rays, and chimaeras. Most are poorly known, largely due to their historically low economic value, and thus, low prioritization for research efforts and targeted sampling. Globally, many deep-sea fisheries have proven to be unsustainable, as deep-sea species are generally characterised with life history traits, resulting in low biological productivity. Although generally not targeted, there is a lack of data on New Zealand deep-sea chondrichthyans, despite regularly occurring as bycatch, with no mitigation in place to limit catches.   This thesis described aspects of life histories for data deficient deep-sea chondrichthyans caught as bycatch in New Zealand deep-sea fisheries. In Chapter II, research trawl survey data were used to describe and evaluate length-weight relationships, which were found to greatly differ from parameters reported by FishBase. This was followed by the application of a set of models to detect changes in weight at length relationships, and assess if these changes correspond to biological or ecological events, such as length-at-maturity or ontogenetic changes in diet.   Chapter III evaluates deep-sea chondrichthyan aggregations and social associations. Not all species were found to engage in aggregative behaviour, but those that did suggested patterns of sex- and size-specific associations which varied with catch density. Adult females were caught most frequently in low densities and were highly associated with other adult females, adult males consistently highly associated with each other, and the highest density catches were dominated by juvenile individuals. These trends may be driven by factors such as foraging, predator avoidance or sexual conflict avoidance.   Chapters IV, V, and VI examine, respectively, details of the reproduction, life history, and diet of prickly dogfish (Oxynotus bruniensis), longnose spookfish (Harriotta raleighana) and Pacific spookfish (Rhinochimaera pacifica), and brown chimaera (Chimaera carophila) and black ghost shark (Hydrolagus homonycteris). All species were found to have life histories characteristic of low productivity, including reaching maturation at a large proportion of their maximum length, and having low fecundity. Additional novel biological results included: DNA identification of prey revealed that O. bruniensis preyed exclusively on the egg capsules of holocephalans, potentially making it the only known elasmobranch with a diet reliant solely upon other chondrichthyans; sperm storage was confirmed in female H. raleighana, R. pacifica, and C. carophila; and sexual dimorphism in snout length was found in H. raleighana, where male relative snout size increased at sexual maturity, suggesting that the snout is a secondary sexual characteristic.   The depth range of most New Zealand deep-sea chondrichthyans may provide some refuge from current fishing activity. However, results from this thesis have suggested that the species examined here have life histories characteristic of low productivity, and engage in behaviours that will have implications for selective mortality by spatially or temporally stratified fishing. Oxynotus bruniensis, in particular, is likely at higher risk from the impact of fishing than currently estimated, given its reproductive characteristics, highly specialised diet, and distribution overlap with deep-sea fisheries. Continued monitoring and a greater collection of biological data from additional and alternative sources (e.g. fisheries observer program, local fishers, underwater vehicles and video) is recommended to fully understand and negate mortality from human activities.</p>

scholarly journals Ecology of New Zealand Deep-sea Chondrichthyans

2021 ◽  
Author(s):  
◽  
Brit Finucci
Keyword(s):  
Life History ◽  
New Zealand ◽  
Deep Sea ◽  
Life Histories ◽  
Biological Data ◽  
Trawl Survey ◽  
Depth Range ◽  
Ontogenetic Changes ◽  
Adult Females ◽  
The Impact

<p>Deep-sea chondrichthyans represent nearly half of the known species of sharks, rays, and chimaeras. Most are poorly known, largely due to their historically low economic value, and thus, low prioritization for research efforts and targeted sampling. Globally, many deep-sea fisheries have proven to be unsustainable, as deep-sea species are generally characterised with life history traits, resulting in low biological productivity. Although generally not targeted, there is a lack of data on New Zealand deep-sea chondrichthyans, despite regularly occurring as bycatch, with no mitigation in place to limit catches.   This thesis described aspects of life histories for data deficient deep-sea chondrichthyans caught as bycatch in New Zealand deep-sea fisheries. In Chapter II, research trawl survey data were used to describe and evaluate length-weight relationships, which were found to greatly differ from parameters reported by FishBase. This was followed by the application of a set of models to detect changes in weight at length relationships, and assess if these changes correspond to biological or ecological events, such as length-at-maturity or ontogenetic changes in diet.   Chapter III evaluates deep-sea chondrichthyan aggregations and social associations. Not all species were found to engage in aggregative behaviour, but those that did suggested patterns of sex- and size-specific associations which varied with catch density. Adult females were caught most frequently in low densities and were highly associated with other adult females, adult males consistently highly associated with each other, and the highest density catches were dominated by juvenile individuals. These trends may be driven by factors such as foraging, predator avoidance or sexual conflict avoidance.   Chapters IV, V, and VI examine, respectively, details of the reproduction, life history, and diet of prickly dogfish (Oxynotus bruniensis), longnose spookfish (Harriotta raleighana) and Pacific spookfish (Rhinochimaera pacifica), and brown chimaera (Chimaera carophila) and black ghost shark (Hydrolagus homonycteris). All species were found to have life histories characteristic of low productivity, including reaching maturation at a large proportion of their maximum length, and having low fecundity. Additional novel biological results included: DNA identification of prey revealed that O. bruniensis preyed exclusively on the egg capsules of holocephalans, potentially making it the only known elasmobranch with a diet reliant solely upon other chondrichthyans; sperm storage was confirmed in female H. raleighana, R. pacifica, and C. carophila; and sexual dimorphism in snout length was found in H. raleighana, where male relative snout size increased at sexual maturity, suggesting that the snout is a secondary sexual characteristic.   The depth range of most New Zealand deep-sea chondrichthyans may provide some refuge from current fishing activity. However, results from this thesis have suggested that the species examined here have life histories characteristic of low productivity, and engage in behaviours that will have implications for selective mortality by spatially or temporally stratified fishing. Oxynotus bruniensis, in particular, is likely at higher risk from the impact of fishing than currently estimated, given its reproductive characteristics, highly specialised diet, and distribution overlap with deep-sea fisheries. Continued monitoring and a greater collection of biological data from additional and alternative sources (e.g. fisheries observer program, local fishers, underwater vehicles and video) is recommended to fully understand and negate mortality from human activities.</p>

Life histories, ecological tolerance limits, and the evolution of geographic range size in Eucalyptus (Myrtaceae)

2005 ◽  
Vol 53 (6) ◽  
pp. 501 ◽  
Author(s):  
Sally Mathews ◽  
Stephen P. Bonser
Keyword(s):  
Life History ◽  
Drought Tolerance ◽  
Life Histories ◽  
Spatial Scales ◽  
Geographic Range ◽  
Range Size ◽  
Tolerance Limits ◽  
Physiological Tolerance ◽  
Australian Continent ◽  
The Impact

Current theories explaining variability in species geographic range sizes in plants tend to focus on how traits associated with either physiological tolerance limits or life histories are related to range size. In trees, aspects of both physiological tolerance (e.g. drought tolerance) and life history (e.g. life span and growth rate) are related to stem traits such as wood density and height relative to diameter. We examined how the evolution of stem traits is related to geographic range sizes in Eucalyptus at two spatial scales: across the Australian continent and within the wet forests near the east coast of Australia. Geographic range sizes were estimated from herbarium records. Stem trait data were collected from both natural populations and published sources. We used phylogenetically independent contrasts to test for evolutionary associations between stem traits and geographic range sizes. Across Australia, the evolution of stem traits conferring drought tolerance were not consistently associated greater range sizes. This was surprising since arid and semi-arid environments are geographically expansive. Within the eastern forests, the evolution of stem traits defining slow growing, competitively dominant life histories were associated with greater range sizes. These stem traits should confer both a capacity to disperse into previously unoccupied habitats and the ability to persist in habitats already occupied. Traits associated with physiological tolerance and life history had significant effects on the evolution of range sizes in Eucalyptus. However, we demonstrate that the impact of these traits on range size evolution depends on both environmental conditions and the scale at which these traits are examined.

Notocotylus tadornae n.sp. and Notocotylus gippyensis (Beverley-Burton, 1958) (Trematoda: Notocotylidae) from waterfowl in New Zealand: morphology, life history and systematic relations

1977 ◽  
Vol 51 (4) ◽  
pp. 365-372 ◽  
Author(s):  
Stewart A. Bisset
Keyword(s):  
Life History ◽  
New Zealand ◽  
Intermediate Host ◽  
Life Histories ◽  
Potamopyrgus Antipodarum

ABSTRACTNotocotylus tadornae n.sp. is described from the New Zealand paradise shelduck Tadorna variegata (Gmelin), and Notocotylus gippyensis (Beverley-Burton, 1958), is recorded from three waterfowl species in New Zealand. The life histories of both species are shown to involve an hydrobiid snail Potamopyrgus antipodarum, as intermediate host. The taxonomic affiliations of N. tadornae and N. gippyensis are discussed.

scholarly journals Slow Life History Leaves Endangered Snake Vulnerable to Illegal Poaching

2020 ◽  
Author(s):  
Chris Jolly ◽  
Brenton von Takach ◽  
Jonathan Webb
Keyword(s):  
Life History ◽  
Population Growth ◽  
Life Histories ◽  
Extinction Risk ◽  
Adult Mortality ◽  
Sensitivity Analyses ◽  
Wildlife Trade ◽  
Pet Trade ◽  
The Impact ◽  
Negative Population

Abstract Global wildlife trade is a multibillion-dollar industry and a significant driver of vertebrate extinction risk. Yet, few studies have quantified the impact of wild harvesting for the illicit pet trade on populations. Long-lived species, by virtue of their slow life history characteristics, may be unable to sustain even low levels of harvesting. Here, we assessed the impact of illegal poaching on a metapopulation of endangered broad-headed snakes (Hoplocephalus bungaroides) at gated (protected) and ungated (unprotected) populations. Because broad-headed snakes are long-lived, grow slowly and reproduce infrequently, populations are likely vulnerable to increases in adult mortality. Long-term data revealed that annual survival rates of snakes were significantly lower in the ungated population than the gated population, consistent with the hypothesis of human removal of snakes for the pet trade. Population viability analysis showed that the ungated population has a strongly negative population growth rate and is only prevented from ultimate extinction by dispersal of small numbers of individuals from the gated population. Sensitivity analyses showed that the removal of a small number of adult females was sufficient to impose negative population growth and suggests that threatened species with slow life histories are likely to be especially vulnerable to illegal poaching.

scholarly journals Simulated mining-related sedimentation impacts on the deep-sea macrofauna of the Chatham Rise, New Zealand

2021 ◽  
Author(s):  
Campbell Murray
Keyword(s):  
Community Structure ◽  
New Zealand ◽  
Deep Sea ◽  
Benthic Communities ◽  
Sampling Period ◽  
Mining Area ◽  
Warning Sign ◽  
Disturbed Areas ◽  
One Year ◽  
The Impact

<p>With the possibility of deep-sea mining of marine mineral resources occurring in the near future, it is necessary to understand the potential impacts that mining may have on benthic communities. Previous simulated mining experiments have observed direct impacts of deep-sea mining (e.g., faunal mortality); however, indirect impacts of sedimentation were not understood. In New Zealand, there has been interest in mining the seabed of the Chatham Rise, but mining consents have been refused, partly due to the uncertainties of sedimentation impacts on benthic communities. A disturbance experiment conducted in 2019 on the Rise used a modified agricultural plough designed to create a sediment cloud that could result from mining. This disturbance was used to assess the resilience of benthic communities to sedimentation in a proposed future mining area. Macrofaunal and sediment samples were collected with a multicorer before, immediately after and one year after disturbance to assess the impact on the community and its ability to recover. Samplingevents took place in disturbed (physically run over by the plough and subjected to sedimentation) and undisturbed areas (subjected to sedimentation only) at each sampling period. Macrofaunal abundance significantly decreased in disturbed areas after disturbancebut not in undisturbed areas. However, community structure changed in both areas after disturbance; in disturbed areas this was mostly driven by changes in numerically dominant fauna, but in undisturbed areas by the more sensitive fauna which may provide an early warning sign for further changes under increased sedimentation. One year after disturbance, community structure had recovered in both areas. Abundance-based community structure correlated most strongly with C:N molar ratios in the sediment which increased after disturbance. Ecosystem function was measured by sediment community oxygen consumption (SCOC) which increased similarly in both disturbed and undisturbed areas after disturbance; SCOC may be a more sensitive measure than community structure in assessing sedimentation impacts. No correlations were found between SCOC and macrofaunal abundance, biomass, diversity or bacterial abundance. The results of this research are useful for managing the impacts of industries where sedimentation is an issue, such as for bottom trawl fisheries and deep-sea mining. The results highlight the importance of leaving unmined patches of seabed adjacent to or within mined areas, to aid the recovery of macrofaunal communities subjected to mining disturbance.</p>

scholarly journals The spotted flounder, Azygopus flemingi Nielsen 1961 (Pisces: Pleuronectiformes: Rhombosoleidae), from deep waters off New Zealand: a second valid species of Azygopus Norman 1926, with notes on distribution, size, maturity, and ecology

Zootaxa ◽  
2012 ◽  
Vol 3297 (1) ◽  
pp. 1 ◽  
Author(s):  
THOMAS A. MUNROE
Keyword(s):  
New Zealand ◽  
Deep Sea ◽  
Maximum Size ◽  
Valid Species ◽  
Depth Range ◽  
Blind Side ◽  
Type Specimens ◽  
Late 20Th Century ◽  
Ocular Side ◽  
Deep Waters

Since its description, Azyygopus Norman, 1926 was considered by subsequent authors to be a monotypic genus in the Or-der Pleuronectiformes comprised only of A. pinnifasciatus Norman, 1926, known from deep waters (90–900 m, usually200–600 m) off the southern and southeastern coasts of Australia. In 1961, a subspecies, A. pinnifasciatus flemingi Niels-en, was described based on three specimens collected at 610 m in the Tasman Sea off the South Island, New Zealand. Fromits description to contemporary literature evaluating its status, recognition of A. p. flemingi as a distinct taxon has beenrejected by all but two studies reporting on Azygopus from New Zealand waters. Until the late 20th century, specimens ofAzygopus had been rarely collected off New Zealand and little was known about these fishes. Over the past 25 years, col-lecting by scientific expeditions and expanding deep-sea fisheries have captured over 195 specimens of Azygopus from avariety of deep-sea locations around New Zealand. Recently-captured specimens of Azygopus collected around New Zea-land and deposited in fish collections have been identified as either A. pinnifasciatus Norman or A. flemingi Nielsen, sug-gesting the possibility that two species of Azygopus occur in New Zealand waters. This study examined the holotype, aparatype, and 25 non-type specimens of A. pinnifasciatus collected off Australia, and the most comprehensive series ofspecimens of Azygopus collected from New Zealand waters. These specimens included the holotype and two paratypes ofA. p. flemingi and 191 other specimens collected from throughout the entire depth range (153–942 m) and representingwide coverage of geographic areas around New Zealand where Azygopus have been collected. Comparisons of these spec-imens indicate that a second species, A. flemingi Nielsen, should be recognized in the genus Azygopus, and that this speciesis the only member of this genus occurring in New Zealand waters. Azygopus flemingi is readily distinguished from A.pinnifasciatus by conspicuous differences in ocularand blind-side color patterns, in numbers of ocular-side pelvic-finrays, total vertebrae, lateral-line scales, and gillrakers on the first gill arch, morphology of blind-side scales and squama-tion patterns, length of blind-side pectoral fins, presence/absence of scales between upper jaw and ventral margin of lowereye, and pigment patterns on dorsal and anal fins of adults. Adult A. flemingi and A. pinnifasciatus are sexually dimorphic in several features. Data on maximum size and size at maturity, and depth of occurrence are summarized for A. flemingi.

Review of life history parameters and preliminary age estimates of some New Zealand deep-sea fishes

2020 ◽  
pp. 1-27
Author(s):  
Peter J. McMillan ◽  
Alan C. Hart ◽  
Peter L. Horn ◽  
Dianne M. Tracey ◽  
Caoimhghin Ó Maolagáin ◽  
...  
Keyword(s):  
Life History ◽  
New Zealand ◽  
Deep Sea ◽  
Life History Parameters ◽  
Age Estimates

Using length–mass relationships to estimate life history: an application to deep-sea fishes

2019 ◽  
Vol 76 (5) ◽  
pp. 723-739
Author(s):  
Brittany Finucci ◽  
Matthew R. Dunn ◽  
Richard Arnold
Keyword(s):  
Life History ◽  
Deep Sea ◽  
Biological Data ◽  
Data Sets ◽  
Biological Factors ◽  
Fisheries Science ◽  
Large Databases ◽  
Expected Length ◽  
Data Deficient ◽  
Using Data

Length–mass relationships, while often overlooked, form the basis of many fisheries science applications. Fisheries-independent research surveys compile large databases of biological data that could hold a wealth of information regarding species’ life history, which, for many, are data deficient and infrequently sampled. A flexible model using permutations of a broken stick and variance shift was applied to length–mass relationships to evaluate changes in the mean or variability of mass-at-length using data from deep-sea fishes and focusing on particularly poorly known deep-sea chondrichthyans. Changes in body shape and (or) in the scale of variability around mean mass-at-length were estimated for most species (94% of data sets examined). Such changes seemed likely to be correlated with biological factors, such as the onset of reproduction; 70% of length estimates for a variance shift correlated with the expected length-at-maturity. The model presented here could be applied to any fish where length and mass data are available, providing a way to estimate, validate, and investigate biological factors in species where macroscopic evaluations are unavailable or difficult to estimate.

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