Marine reserves for Caribbean spiny lobster: empirical evaluation and theoretical metapopulation recruitment dynamics

2001 ◽  
Vol 52 (8) ◽  
pp. 1589 ◽  
Author(s):  
Romuald N. Lipcius ◽  
William T. Stockhausen ◽  
David B. Eggleston
Keyword(s):  
Habitat Quality ◽  
Marine Reserves ◽  
Spiny Lobster ◽  
Empirical Evaluation ◽  
Circulation Model ◽  
Transport Processes ◽  
Adult Density ◽  
Fishing Mortality ◽  
Before And After ◽  
Optimal Reserve

Field data on spiny-lobster abundance, habitat quality, and hydrodynamic transport patterns for a reserve (ECLSP) and three exploited sites (CI, EI, LSI) were used to assess reserve success in reducing fishing mortality and increasing theoretical metapopulation recruitment. Fishing mortality was estimated empirically by quantification of lobster density at ECLSP and the three exploited sites before and after the start of the fishing season in two years. Fishing mortality was estimated to be 47–98% lower at the reserve. Using a circulation model , we theoretically assessed effectiveness of ECLSP and nominal reserves at the exploited sites in augmenting recruitment through redistribution of larvae to all sites. Larvae discharged from ECLSP and EI recruited throughout Exuma Sound, whereas those from LSI and CI recruited only to CI and LSI. Hence, only reserves at EI and ECLSP would be suitable for metapopulation recruitment. In selecting an optimal reserve for metapopulation recruitment, use of information on habitat quality or adult density did not yield a higher probability of success than did determining the reserve location by chance. The only successful strategy was one that used information on transport processes. Designation of effective marine reserves therefore requires careful attention to metapopulation dynamics and recruitment processes.

The use of marine reserves in evaluating the dive fishery for the warty sea cucumber (Parastichopus parvimensis) in California, U.S.A.

2001 ◽  
Vol 58 (9) ◽  
pp. 1773-1781 ◽  
Author(s):  
Stephen C Schroeter ◽  
Daniel C Reed ◽  
David J Kushner ◽  
James A Estes ◽  
David S Ono
Keyword(s):  
Stock Assessment ◽  
Marine Reserves ◽  
Dependent Data ◽  
Fishing Mortality ◽  
Catch Per Unit Effort ◽  
Before And After ◽  
The Status ◽  
Long Term Monitoring ◽  
Term Monitoring

Management of sustainable fisheries depends upon reliable estimates of stock assessment. Assessment of many stocks is based entirely on fishery-dependent data (e.g., catch per unit effort), which can be problematic. Here we use fishery-independent data on stock size, collected within and outside of no-take reserves before and after the onset of fishing, to evaluate the status of the dive fishery for warty sea cucumbers, Parastichopus parvimensis, in southern California. Long-term monitoring data showed that abundance decreased throughout the Channel Islands within 3–6 years after the onset of fishing. No significant changes in the abundance of P. parvimensis were observed at the two non-fished reserve sites, although densities tended to increase following onset of the fishery. Before–after, control–impact (BACI) analyses of seven fished and two non-fished sites implicated fishing mortality as the cause of 33–83% stock declines. In sharp contrast, stock assessment based on CPUE data showed no declines and a significant increase at one island. To date, most discussion on marine reserves has focused on the protection and enhancement of exploited populations. Our study demonstrates the critically important, but often overlooked, role that marine reserves can play in providing reliable information on stock assessment.

scholarly journals On the spillover effect and optimal size of marine reserves for sustainable fishing yields

2019 ◽  
Author(s):  
Nao Takashina
Keyword(s):  
Numerical Simulations ◽  
Migration Rate ◽  
Marine Reserves ◽  
Marine Reserve ◽  
Practical Importance ◽  
Spillover Effect ◽  
Optimal Size ◽  
Fishing Mortality ◽  
Optimal Reserve ◽  
Reserve Size

AbstractMarine reserves are an essential component of modern fishery management. Marine reserves, which represent a management tradeoff between harvesting and conservation, are fundamental to maintenance of fisheries. Finding optimal reserve sizes that improve fishing yields is not only of theoretical interest, but also of practical importance to facilitate decision making. Also, since the migratory behavior of some species influences the spillover effect of a marine reserve, this is a key consideration when assessing performance of marine reserves. The relationship between optimal reserve size and migration rate/mode has not been well studied, but it is fundamental to management success. Here, I investigate optimal reserve size and its management outcome with different levels of spillover via a simple two-patch mathematical model. In this model, one patch is open to fishing, and the other is closed. The two-patch model is aggregated by single-population dynamics when the migration rate is sufficiently larger than the growth rate of a target species. At this limit, I show that an optimal reserve size exists when pre-reserve fishing occurs at fishing mortality larger than fMSY, the fishing mortality at the maximum sustainable yield (MSY). Also, the fishing yield at an optimal reserve size becomes as large as MSY at the limit. Numerical simulations at various migration rates between the two patches suggest that the maximum harvest under management with a marine reserve is achieved at this limit. This contrasts with the conservation benefit which is maximized at an intermediate migration rate. Numerical simulations show that the above-mentioned condition derived from the aggregated model is necessary when the migration rate is not sufficiently large, and that a moderate migration rate is further necessary for an optimal reserve size to exist. However, high fishing mortality reduces this requirement.

scholarly journals On the spillover effect and optimal size of marine reserves for sustainable fishing yields

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9798
Author(s):  
Nao Takashina
Keyword(s):  
Numerical Simulations ◽  
Migration Rate ◽  
Marine Reserves ◽  
Marine Reserve ◽  
Practical Importance ◽  
Spillover Effect ◽  
Optimal Size ◽  
Fishing Mortality ◽  
Optimal Reserve ◽  
Reserve Size

Marine reserves are an essential component of modern fishery management. Marine reserves, which represent a management tradeoff between harvesting and conservation, are fundamental to maintenance of fisheries. Finding optimal reserve sizes that improve fishing yields is not only of theoretical interest, but also of practical importance to facilitate decision making. Also, since the migratory behavior of some species influences the spillover effect of a marine reserve, this is a key consideration when assessing performance of marine reserves. The relationship between optimal reserve size and migration rate/mode has not been well studied, but it is fundamental to management success. Here, I investigate optimal reserve size and its management outcome with different levels of spillover via a simple two-patch mathematical model. In this model, one patch is open to fishing, and the other is closed. The two-patch model is aggregated by single-population dynamics when the migration rate is sufficiently larger than the growth rate of a target species. At this limit, I show that an optimal reserve size exists when pre-reserve fishing occurs at fishing mortality larger than fMSY, the fishing mortality at the maximum sustainable yield (MSY). Also, the fishing yield at an optimal reserve size becomes as large as MSY at the limit. Numerical simulations at various migration rates between the two patches suggest that the maximum harvest under management with a marine reserve is achieved at this limit. This contrasts with the conservation benefit which is maximized at an intermediate migration rate. Numerical simulations show that the above-mentioned condition for an optimal reserve size to exist derived from the aggregated model is necessary when the migration rate is not sufficiently large, and that a moderate migration rate is further necessary for an optimal reserve size to exist. However, high fishing mortality reduces this requirement.

scholarly journals Effects of surface current/wind interaction in an eddy-rich general ocean circulation simulation of the Baltic Sea

2016 ◽  
Author(s):  
H. Dietze ◽  
U. Löptien
Keyword(s):  
Baltic Sea ◽  
Ocean Circulation ◽  
Surface Waters ◽  
Algal Blooms ◽  
Circulation Model ◽  
Transport Processes ◽  
Surface Currents ◽  
Wind Effects ◽  
The Baltic Sea ◽  
The Baltic

Abstract. Deoxygenation in the Baltic Sea endangers fish yields and favours noxious algal blooms. Yet, vertical transport processes ventilating the oxygen-deprived waters at depth and replenishing nutrient-deprived surface waters (thereby fuelling export of organic matter to depth), are not comprehensively understood. Here, we investigate the effects of the interaction between surface currents and winds (also referred to as eddy/wind effects) on upwelling in an eddy-rich general ocean circulation model of the Baltic Sea. Contrary to expectations we find that accounting for current/wind effects does inhibit the overall vertical exchange between oxygenated surface waters and oxygen-deprived water at depth. At major upwelling sites, however, as e.g. off the south coast of Sweden and Finland, the reverse holds: the interaction between topographically steered surface currents with winds blowing over the sea results in a climatological sea surface temperature cooling of 0.5 K. This implies that current/wind effects drive substantial local upwelling of cold and nutrient-replete waters.

scholarly journals Monsoonal control on a delayed response of sedimentation to the 2008 Wenchuan earthquake

2019 ◽  
Vol 5 (6) ◽  
pp. eaav7110 ◽  
Author(s):  
Fei Zhang ◽  
Zhangdong Jin ◽  
A. Joshua West ◽  
Zhisheng An ◽  
Robert G. Hilton ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
Transport Processes ◽  
Delayed Response ◽  
2008 Wenchuan Earthquake ◽  
The 2008 Wenchuan Earthquake ◽  
Depositional Processes ◽  
Before And After ◽  
Sediment Transfer ◽  
Large Earthquakes ◽  
Earthquake Cycles

Infrequent extreme events such as large earthquakes pose hazards and have lasting impacts on landscapes and biogeochemical cycles. Sediments provide valuable records of past events, but unambiguously identifying event deposits is challenging because of nonlinear sediment transport processes and poor age control. Here, we have been able to directly track the propagation of a tectonic signal into stratigraphy using reservoir sediments from before and after the 2008 Wenchuan earthquake. Cycles in magnetic susceptibility allow us to define a precise annual chronology and identify the timing and nature of the earthquake’s sedimentary record. The grain size and Rb/Sr ratio of the sediments responded immediately to the earthquake. However, the changes were muted until 2 years after the event, when intense monsoonal runoff drove accumulation of coarser grains and lower Rb/Sr sediments. The delayed response provides insight into how climatic and tectonic agents interact to control sediment transfer and depositional processes.

Fish Habitat: Essential Fish Habitat and Rehabilitation

1999 ◽  
Keyword(s):  
Field Experiment ◽  
Fish Habitat ◽  
Spiny Lobster ◽  
Basic Research ◽  
Florida Keys ◽  
Ecological Processes ◽  
Juvenile Recruitment ◽  
Before And After ◽  
Individual Survival ◽  
Concrete Blocks

<em>Abstract</em> .—Basic research on the settlement and postsettlement ecology of spiny lobster <em>Panulirus argus </em> has led to an application with the potential to replace lost natural refuge with artificial shelters intended for the vulnerable small juvenile stages. We began investigating ecological processes regulating juvenile spiny lobster recruitment in the Florida nursery in the mid-1980s. An unprecedented massive die-off of sponges in the middle Florida Keys followed cyanobacterial blooms in 1991–1993, ultimately affecting about 300 km2 of a region providing approximately one-fifth of total juvenile recruitment. Before 1991, crevices in sponges provided diurnal refuge from predators for about 70% of juveniles <50 mm carapace length. On the basis of sampling done before and after sponge loss, we estimated that juvenile abundance declined by 30–50% on spongeless sites without alternative shelter, resulting in a decrease of annual nurserywide potential of up to 10%. Results of a field experiment evaluating the relative influences of the magnitude of settlement and availability of crevice shelter on juvenile recruitment, fortuitously begun before the sponge die-off, showed that juvenile survival and abundance were sustained on small 0.02- to 0.07-ha test sites provided with supplemental artificial shelters (slotted concrete blocks). In the absence of sponges, survival of microwire-tagged juveniles on the shelter-supplemented sites was about six times higher than that on unsupplemented sites. On the basis of our earlier ecological findings, we devised a feasibility study to test whether the artificial shelters could replace lost sponge shelter for juvenile lobsters on a large scale. It took the form of a field experiment using 240 shelters spread over 1-ha sites located amid hard substrate denuded of sponges. The shelters provided substitute crevices, supporting juvenile lobster recruitment approximating that in areas with good sponge cover. This outcome exemplifies the essential value of initial basic research that provides understanding of the ecological processes regulating individual survival and, ultimately, the character and dynamics of the fishery population. Such an approach, and the information it provides, is necessary to successful rehabilitation of essential habitat or restocking of natural populations. Moreover, conducting basic research can help prevent the waste of precious time, funds, income, and human effort that typically has occurred in past failed attempts that were undertaken with insufficient knowledge. We urge the fisheries-ecology discipline and support agencies to promote strongly the primacy of research on basic processes.

scholarly journals Effects of the planetary waves on the MLT airglow

2017 ◽  
Vol 35 (5) ◽  
pp. 1023-1032 ◽  
Author(s):  
Fabio Egito ◽  
Hisao Takahashi ◽  
Yasunobu Miyoshi
Keyword(s):  
General Circulation ◽  
Atomic Oxygen ◽  
Lower Thermosphere ◽  
Lower Boundary ◽  
Circulation Model ◽  
Vertical Transport ◽  
Transport Processes ◽  
Planetary Waves ◽  
Emission Rates ◽  
Middle Latitudes

Abstract. The planetary-wave-induced airglow variability in the mesosphere and lower thermosphere (MLT) is investigated using simulations with the general circulation model (GCM) of Kyushu University. The model capabilities enable us to simulate the MLT OI557.7 nm, O2b(0–1), and OH(6–2) emissions. The simulations were performed for the lower-boundary meteorological conditions of 2005. The spectral analysis reveals that at middle latitudes, oscillations of the emission rates with the period of 2–20 days appear throughout the year. The 2-day oscillations are prominent in the summer and the 5-, 10-, and 16-day oscillations dominate from the autumn to spring equinoxes. The maximal amplitude of the variations induced by the planetary waves was 34 % in OI557.7 nm, 17 % in O2b(0–1), and 8 % in OH(6–2). The results were compared to those observed in the middle latitudes. The GCM simulations also enabled us to investigate vertical transport processes and their effects on the emission layers. The vertical transport of atomic oxygen exhibits similar periodic variations to those observed in the emission layers induced by the planetary waves. The results also show that the vertical advection of atomic oxygen due to the wave motion is an important factor in the signatures of the planetary waves in the emission rates.

An Analysis of the Linkage of Pacific Subtropical Cells with the Recharge–Discharge Processes in ENSO Evolution

2015 ◽  
Vol 28 (9) ◽  
pp. 3786-3805 ◽  
Author(s):  
Han-Ching Chen ◽  
Chung-Hsiung Sui ◽  
Yu-Heng Tseng ◽  
Bohua Huang
Keyword(s):  
El Niño ◽  
General Circulation ◽  
El Nino ◽  
Causal Relation ◽  
Circulation Model ◽  
Transport Processes ◽  
Water Volume ◽  
Time Lags ◽  
Wind Stress Curl ◽  
Time Intervals

Abstract The Simple Ocean Data Assimilation, version 2.2.4 (SODA 2.2.4), analysis for the period of 1960–2010 is used to study the variability of Pacific subtropical cells (STCs) and its causal relation with tropical climate variability. Results show that the interior STC transport into the equatorial basin through 9°S and 9°N is well connected with equatorial sea surface temperature (SST) (9°S–9°N, 180°–90°W). The highest correlation at interannual time scales is contributed by the western interior STC transport within 160°E and 130°W. It is known that the ENSO recharge–discharge cycle experiences five stages: the recharging stage, recharged stage, warmest SST stage, discharging stage, and discharged stage. A correlation analysis of interior STC transport convergence, equatorial warm water volume (WWV), wind stress curl, and SST identifies the time intervals between the five stages, which are 8, 10, 2, and 8 months, respectively. A composite analysis for El Niño–developing and La Niña–developing events is also performed. The composited ENSO evolutions are in accordance with the recharge–discharge theory and the corresponding time lags between the above denoted five stages are 4–12, 6, 2, and 4 months, respectively. For stronger El Niño events, the discharge due to interior STC transport at 9°N terminates earlier than that at 9°S because of the southward migration of westerly winds following the El Niño peak phase. This study clarifies subsurface transport processes and their time intervals, which are useful for refinement of theoretical models and for evaluating coupled ocean–atmosphere general circulation model results.

The Effect of Reduction of Fishing Effort on Yield

1962 ◽  
Vol 19 (4) ◽  
pp. 521-529 ◽  
Author(s):  
Syoiti Tanaka
Keyword(s):  
Mortality Rate ◽  
Sudden Change ◽  
Japan Sea ◽  
Fish Population ◽  
Fishing Effort ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Yield Curves ◽  
Before And After ◽  
Steady Level

When a fish population has been depleted by heavy exploitation, with the yield from the population maintaining an unfavourable level, it is usual to expect that the situation will be improved by reduction of fishing effort. Following a sudden reduction of fishing mortality, p, from p1 to p2 at time τ = 0, the yield at once decreases and then increases gradually until it reaches another steady level higher than the former level.The present paper deals, using Baranov's model, with the transition stage of the population following a sudden change in p, as well as with the steady state before and after the change. Relations between equilibrium yield and fishing mortality rate (effort-yield curves) are calculated for various values of the parameters, λ0 (= l0/u, where l0 is the length of a recruit and u is the yearly increase in length), q (natural mortality rate), and b (remaining life span of a fish at the time of recruitment) (Fig. 2). It is noteworthy that for species that grow slowly after recruitment, i.e. when λ0 is large, reduction of fishing would have scarcely any effect on the yield (Fig. 4).Yield curves for the period of transition from the present to various lower levels of fishing are calculated for the case in which λ0 = 4, q = 0.15, b = 10 and p1 = 1.35. These represent parameters for the present state of the stock of sohachi flounders Cleisthenes herzensteini (Schmidt), in the southwestern area of the Japan Sea (Fig. 5).Possible density effects on growth rate and natural mortality rate, which are briefly discussed, appear to diminish considerably the effectiveness of any reduction in fishing effort (Fig. 6).

Hydrodynamic decoupling of recruitment, habitat quality and adult abundance in the Caribbean spiny lobster: source - sink dynamics?

1997 ◽  
Vol 48 (8) ◽  
pp. 807 ◽  
Author(s):  
R. N. Lipcius ◽  
W. T. Stockhausen ◽  
D. B. Eggleston ◽  
L. S. Marshall Jr ◽  
B. Hickey
Keyword(s):  
Habitat Quality ◽  
Large Scale ◽  
Marine Reserve ◽  
Spiny Lobster ◽  
Marine Species ◽  
Nursery Habitat ◽  
Panulirus Argus ◽  
The Caribbean ◽  
Juvenile Density ◽  
Adult Abundance

Marine species possess dispersive stages that interconnect subpopulations, which may inhabit ‘source’ and ‘sink’ habitats, where reproduction and emigration either exceed or fall short of mortality and immigration, respectively. Postlarval supply, juvenile density and adult abundance of the Caribbean spiny lobster, Panulirus argus, were measured at four widely separated sites spanning >100 km in Exuma Sound, Bahamas. Adult abundance was lowest at a site with the highest postlarval supply and little nursery habitat; hence, it was tentatively classified as a sink. Circulation in Exuma Sound is dominated by large-scale gyres which apparently concentrate and advect postlarvae toward the nominal sink. The remaining three sites, including one marine reserve, had higher adult abundances despite lower postlarval supply, and are therefore tentatively classified as sources. Postlarval supply is probably decoupled from adult abundance by physical transport. Adult abundance is likely decoupled from postlarval supply by the effects of varying habitat quality upon postlarval and juvenile survival, as indicated by non-significant differences among sites in juvenile density. It appears that some sites with suitable settlement and nursery habitat are sources of spawning stock for Panulirus argus, whereas others with poor habitat are sinks despite sufficient postlarval influx.

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