Life Sciences Commons^™

Can Ecosystem-Based Deep-Sea Fishing Be Sustained?, Les Watling, R L. Haedrich, J Devine, J Drazen, M R. Dunn, M Gianni, K Baker, G Cailliet, I Figueiredo, P M. Kyne, G Menezes, F Neat, A Orlov, P Duran, J A. Perez, J A. Ardon, J Bezaury, C Revenga, C Nouvian

Marine Sciences Faculty Scholarship

Can there ever be a truly sustainable deep-sea fishery and if

so, where and under what conditions? Ecosystembased

fisheries management requires that this question be

addressed such that habitat, bycatch species, and targeted

fish populations are considered together within an ecosystem

context.

To this end, we convened the first workshop to develop an

ecosystem approach to deep-sea fisheries and to ask whether

deep-sea species could be fished sustainably. The workshop

participants were able to integrate bycatch information into

their framework but found it more difficult to integrate other

ecosystem indicators such as habitat characteristics.

(First two paragraphs from the Executive …

Defining And Implementing Best Available Science For Fisheries And Environmental Science, Policy, And Management, P. J. Sullivan, James Acheson, P. L. Angermeier, T. Faast, J. Flemma, C. M. Jones, E. E. Knudsen, T. J. Minello, D. H. Secor, R. Wunderlich, B. A. Zanetell

Marine Sciences Faculty Scholarship

In the United States, many of the laws governing environmental conservation and management stipulate that the best available science be used as the basis for policy and decision making. The Endangered Species Act, for example, requires that decisions on listing a species as threatened or endangered be made on the basis of the "best scientific and commercial data available." Similarly, National Standard 2 of the Magnuson-Stevens Fishery Conservation and Management Act states that conservation and management measures shall be based on "the best scientific information available." Further, the U.S. Environmental Protection Agency has emphasized the role of best available science …

Uncertainties Of Inherent Optical Properties Obtained From Semianalytical Inversions Of Ocean Color, Peng Wang, Emmanuel S. Boss, Collin Roesler

Marine Sciences Faculty Scholarship

We present a method to quantify the uncertainties in the in-water constituent absorption and backscattering coefficients obtained from an inversion of remotely sensed reflectance (rrs). We first find a set of positive inversion solutions within a given uncertainty range around the values of the inverted rrs. The uncertainties of the solutions are then computed based on the statistics of these solutions. We demonstrate the uncertainty calculation algorithm using a specific semianalytic inversion model applied to both a field and a simulated data set. When the associated uncertainties are taken into account, the inverted parameters are generally within the uncertainties of …

Why Should We Measure The Optical Backscattering Coefficient?, Emmanuel Boss, Dariusz Stramski, Trisha Bergmann, W. Scott Pegau, Marlon Lewis

Marine Sciences Faculty Scholarship

In recent years commercial sensors for in situ determinations of optical backscattering coefficient, b_b, have become available. The small size and low power requirements of these sensors permit deployment from small sensing platforms such as autonomous underwater vehicles, in addition to standard profiling packages. Given their rapid sampling time (sub second) they can collect data with high temporal and spatial resolution (sub meter).

While these are attractive features of any sensor they do not answer the question: why should oceanographers measure b_b?

The short answer is that b_b carries useful information about seawater constituents that …

The New Age Of Hyperspectral Oceanography, Grace Chang, Kevin Mahoney, Amanda Briggs-Whitmire, David D.R. Kohler, Curtis D. Mobley, Marlon Lewis, Mark A. Moline, Emmanuel Boss, Minsu Kim, William Philpot, Tommy D. Dickey

Marine Sciences Faculty Scholarship

A multispectral optical sensor collects data at select wavebands or channels. An example is the Sea-viewing Wide-Field-of-view Sensor (SeaWiFS) ocean color satellite, which measures eight wavebands between 402 and 885 nm (20-40 nm bandwidth with peaks centered around 412, 443, 490, 510, 555, 670, 765, and 865 nm). Optical oceanographers have been using multispectral sensors since the 1980s with great success.

The Role Of Seawater Constituents In Light Backscattering In The Ocean, Dariusz Stramski, Emmanuel Boss, Darek Bogucki, Kenneth J. Voss

Marine Sciences Faculty Scholarship

The significance of light backscattering in the ocean is wide ranging, especially in optical remote sensing. However, the complexity of natural seawater as an optical medium often obscures the measured optical signals to the point that our present-day interpretation and detailed understanding of major sources of backscattering and its variability in the ocean are uncertain and controversial. Here we review the roles played by various seawater constituents in light backscattering and we address a question of 'missing' backscattering. Historically, this question has resulted from a hypothesis that under non-bloom conditions in the open ocean, phytoplankton make a significantly smaller contribution …

Optical Modeling Of Ocean Waters: Is The Case 1 - Case 2 Classification Still Useful?, Curtis D. Mobley, Dariusz Stramski, W. Paul Bissett, Emmanuel Boss

Marine Sciences Faculty Scholarship

…two extreme cases can be identified and separated. Case 1 is that of a concentration of phytoplankton high compared to other particles…. In contrast, the inorganic particles are dominant in case 2.… In both cases dissolved yellow substance is present in variable amounts.… An ideal case 1 would be a pure culture of phytoplankton and an ideal case 2 a suspension of nonliving material with a zero concentration of pigments.

Morel and Prieur emphasized that these ideal cases are not encountered in nature, and they suggested the use of high or low values of the ratio of pigment concentration to …

Toward Closure Of Upwelling Radiance In Coastal Waters, Grace C. Chang, Tommy D. Dickey, Curtis D. Mobley, Emmanuel Boss, W. Scott Pegau

Marine Sciences Faculty Scholarship

We present three methods for deriving water-leaving radiance Lw(λ) and remote-sensing reflectance using a hyperspectral tethered spectral radiometer buoy (HyperTSRB), profiled spectroradiometers, and Hydrolight simulations. Average agreement for 53 comparisons between HyperTSRB and spectroradiometric determinations of Lw(λ) was 26%, 13%, and 17% at blue, green, and red wavelengths, respectively. Comparisons of HyperTSRB (and spectroradiometric) Lw(λ) with Hydrolight simulations yielded percent differences of 17% (18%), 17% (18%), and 13% (20%) for blue, green, and red wavelengths, respectively. The differences can be accounted for by uncertainties in model assumptions and model input data (chlorophyll fluorescence quantum efficiency and the spectral chlorophyll-specific absorption …

Subsurface Maxima Of Phytoplankton And Chlorophyll: Steady-State Solutions From A Simple Model, Katja Fennel, Emmanuel Boss

Marine Sciences Faculty Scholarship

In oligotrophic lakes and oceans, the deep chlorophyll maximum may form independently of a maximum of phytoplankton biomass, because the ratio of chlorophyll to phytoplankton biomass (in units of carbon) increases with acclimation to reduced light and increased nutrient supply at depth. Optical data (beam attenuation as proxy for phytoplankton biomass and chlorophyll fluorescence and absorption as proxies for chlorophyll concentration) and conventional measurements of biovolume, particulate organic carbon, and chlorophyll from two oligotrophic systems (Crater Lake, Oregon, and Sta. ALOHA in the subtropical North Pacific Ocean) are presented and show a vertical separation of the maxima of biomass and …

The Effect Of Bottom Substrate On Inherent Optical Properties: Evidence Of Biogeochemical Processes, Emmanuel Boss, J. Ronald V. Zaneveld

Marine Sciences Faculty Scholarship

Measurements of inherent optical properties (IOP) were conducted over bottoms with different substrates by use of a sampling package mounted on and operated by a SCUBA diver. It was found that in areas of low ambient currents the distribution of IOP varies with bottom type in (1) its value relative to a nearby bottom of different type, (2) its vertical gradient, and (3) its variability. This implies that radiative transfer modeling in shallow environments may need to include, besides the bottom characteristics, the bottom effect on in-water IOP. In tidally flushed shallow banks, vertical and horizontal gradients over scales of …

The Influence Of Bottom Morphology On Reflectance: Theory And Two-Dimensional Geometry Model, J. Ronald V. Zaneveld, Emmanuel Boss

Marine Sciences Faculty Scholarship

The reflectance of the bottom is of importance when interpreting optical data in shallow water. Closure studies of radiative transfer, interpretation of laser line scanner data, lidar, and remote sensing in shallow waters require understanding of the bottom reflectance. In the Coastal Benthic Optical Properties experiment (CoBOP), extensive measurements of the material reflectance (reflectance very close to the bottom) were made. Far field reflectance will be needed in carrying out closure of the radiative transfer model and observed radiometric and inherent optical properties. The far field reflectance is the bottom reflectance that includes the effect of bottom morphology (such as …

Nearshore Physical Processes And Bio-Optical Properties In The New York Bight, G. C. Chang, T. D. Dickey, O. M. Schofield, A. D. Weidemann, E. Boss, W. S. Pegau, M. A. Moline, S. M. Glenn

Marine Sciences Faculty Scholarship

Temporal and spatial variability of physical, biological, and optical properties on scales of minutes to months and meters to ∼50 km are examined using an extensive data set collected on the New York Bight continental shelf during the Hyperspectral Coastal Ocean Dynamics Experiment. Measurements from a midshelf mooring and bottom tripod (∼25 km offshore, 24 m water depth) and two nearshore profiling nodes (∼5 km offshore, 15 m water depth) are utilized to quantify and correlate midshelf and nearshore variability. Towed shipboard undulating profilers and a high-frequency radar (CODAR) array provide complementary spatial data. We show that phytoplankton and dissolved …

Ocean Color Observations Of Eddies During The Summer In The Gulf Of California, W. Scott Pegau, Emmanuel Boss, Antonio Martínez

Marine Sciences Faculty Scholarship

Using SeaWiFS ocean color satellite images collected during 1997-2001, a series of eddies have been observed in the Gulf of California. These eddies are not clearly seen in the summertime sea surface temperature images. The surface circulation between the midriff islands and the mouth of the gulf appears to be dominated by this series of eddies that have an alternating sense of rotation. An eddy pair is observed to extend from Cabo Lobos in each of the three years, suggesting that the eddies are topographically locked. The formation mechanism of the eddies remains unknown; however, we suspect the most likely …

Phase Function Effects On Oceanic Light Fields, Curtis D. Mobley, Lydia K. Sundman, Emmanuel Boss

Marine Sciences Faculty Scholarship

Numerical simulations show that underwater radiances, irradiances, and reflectances are sensitive to the shape of the scattering phase function at intermediate and large scattering angles, although the exact shape of the phase function in the backscatter directions (for a given backscatter fraction) is not critical if errors of the order of 10% are acceptable. We present an algorithm for generating depth–and wavelength-dependent Fournier–Forand phase functions having any desired backscatter fraction. Modeling of a comprehensive data set of measured inherent optical properties and radiometric variables shows that use of phase functions with the correct backscatter fraction and overall shape is crucial …

Confounding The Goals Of Management: Response Of The Maine Lobster Industry To A Trap Limit, James Acheson

Marine Sciences Faculty Scholarship

The behavior of fishermen is often far more complicated than assumed by fisheries managers. Those concerned with the Maine lobster (i.e., American lobster Homarus americanus, hereafter "lobster") fishery have long favored a cap on the number of traps each license holder can use. Fishermen favor trap limits primarily to cut costs and limit congestion, and managers believe such limits will help reduce fishing effort. Yet when trap limits were imposed by the legislature and the lobster zone councils between 1995 and 1998, the number of traps fished in Maine waters increased greatly. A survey of half the lobster license holders …

Biological And Economic Effects Of Increasing The Minimum Legal Size Of American Lobster In Maine, James Acheson, R. Reidman

Marine Sciences Faculty Scholarship

The Northeast Marine Fisheries Board recently completed a comprehensive management plan for American lobster Homarus americanus, the most important provision of which is to raise the legal minimum size of lobsters from 81 to 88.9 mm carapace length incrementally over 5 years. Its objective is to increase egg production and recruitment, and thus reduce the likelihood of stock failure; economic benefits are anticipated for fishermen. However, a model used to analyze the frequency distributions of some 9,000 Maine lobsters demonstrates that in every year the legal minimum size is increased, smaller numbers and less weight of lobsters would be landed …

Attitudes Towards Limited Entry Among Fin Fishermen In Northern New England, James Acheson

Marine Sciences Faculty Scholarship

Management of marine fisheries by "limited entry legislation" promises not only to protect the breeding stock and increase catches,but also to improve economic efficiency and increase returns to fishermen. It will also undoubtedly disrupt existing social and economic relationships. While no limited entry legislation is in effect in New England, fishermen know about the limited entry management option and have strong opinions that are certain to influence politicial support. Some of the 190 Maine and New Hampshire fishermen interviewed favor or oppose such legislation because their own "economic selfinterest" would be positively or negatively affected. Most, however, oppose or favor …