Dataset: juv_fish_bycatch_redux

Name: Species counts from control and gear manipulation trials to reduce bycatch of juvenile fish carried out on fishing vessels in the Northeast Consortium (NEC) in the Southwest coastal Maine from 2011-2012 (NEC_ProjDev project)
Published: 2012-12-14
Keywords: oceans

Cite This Dataset

Spatial Extent: N:43.72163 E:-69.840572 S:43.545562 W:-70.242157

Project:

Northeast Consortium: Project Development (NEC_ProjDev)

Program:

NorthEast Consortium (NEC)

Principal Investigator:

Claire L Enterline (Maine Department of Marine Resources, Maine DMR)

BCO-DMO Data Manager:

Shannon Rauch (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2012-12-14

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Species counts from control and gear manipulation trials to reduce bycatch of juvenile fish carried out on fishing vessels in the Northeast Consortium (NEC) in the Southwest coastal Maine from 2011-2012 (NEC_ProjDev project)

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Description

The Maine Department of Marine Resources, in collaboration with three fishermen, tested five gear manipulations in floating near-shore pound nets to evaluate their effectivness in reducing the incidental take of juvenile American shad (Alosa sapidissima), blueback herring (A. aestivalis), and alewife (A. pseudoharengus), while maintaining the catch quanitity and quality of the target species.

Sampling hauls generally alternated between gear manipulation and control trials on a 3-day rotation. During each trip, a portion of the total catch was sampled for species composition. Length was recorded for a sub-sample of each species.

See also: photographs taken during sampling trips (70.9 MB .zip file)

Other Project Participants:
Michael Brown, Maine Dept. of Inland Fisheries and Wildlife (former project PI)
Rob Bernat (Fisherman)
Brett Gilliam (Fisherman)
Dan Harriman (Fisherman)

References:
Enterline, Claire. Reducing juvenile alewife, blueback, and american shad bycatch in the coastal pound net and floating fish trap fisheries. Northeast Consortium Final Report 11-142.

Methods & Sampling

Control and gear manipulation trials were performed on a 3-day rotation (except for the trials testing the 6" mesh leader). During each trip, the species and size composition of the catch were sampled.

The following five gear types were tested:
(1) a large (8' by 8') soft mesh escape panel, knotless 2" mesh size (at Richmond Island site);
(2) a small (~ 2' by 4') soft mesh escape panel, 3" mesh size (at Bailey Island site);
(3) a 3' by 6' aluminum panel with 3/8" vertical bar spacing (at Bailey Island site);
(4) a 3' by 6' aluminum panel with 1/2" vertical bar spacing (at Bailey Island site);
(5) a large mesh lead to the trap: 6" mesh size (at Hermit Island site).

For catches larger than 1 tray, the catch was sub-sampled using one random tray from the catch. All fish of the sub-sample were identified to the species-level and counted. The total length of the first 100 individuals of each species were measured to the nearest millimeter. For catches of 1 tray or less, the entire catch was sampled; all fish were identified and counted, and the first 100 individuals were measured.

The total catch was either counted in trays or estimated by the fisherman in total pounds (the number of pounds per tray was not estimated). Notes were taken regarding apparent fish behavior in response to the bycatch reduction gear and fishing methods, as well as fishermens' comments regarding the gear manipulations.

Data Processing Description

Parameter names were changed to conform with BCO-DMO conventions. Blanks were replaced with 'nd' to indicate 'no data'.

Data Files

File
juv_fish_bycatch_redux.csv (Comma Separated Values (.csv), 2.34 MB) MD5:397001dd9ff32bc4aaac949c29c3090c Primary data file for dataset ID 3819

More Information about this dataset

Funding Sources

Funding Source	Award Number
NorthEast Consortium	11-142

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
NEC-CE2009-1		2011-06-01	Fishing Vessels	Claire L Enterline (Principal Investigator)	data info

Instruments

Floating Pound Net

Supplied Description:

The nets used in this study were floating pound nets, using floating toggles and buoys at the surface and held taught below the surface using anchors at the corners.

Instrument Type

Generic Name: Floating Pound Net

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/63/

Generic Description:

Pound nets are passive, stationary gear used for live entrapment of fish species. The gear is composed of fiber netting. Floating pound nets use floating toggles and buoys at the surface and are held taught below the surface using anchors.

A pound net consists of: (1) a net body or crib where the entrapment takes place, (2) a least one mesh heart that helps funnel fish into the crib, and (3) a straight leader or hedging which leads fish toward the crib. Fish swimming along the shore are turned toward the crib by the hedging, guided into the heart, and into the crib where they are removed.

(Description from Maryland Dept of Natural Resources)

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
port	Name of the port where the fishing vessel departs from/returns to.	text	site_descrip
trip	The unique identification code given to each haul trip. All trips with the same identification number are part of the same haul effort.	text	haul_id
month_local	2-digit month of year (local) when the trip occurred.	mm (01 to 12)	month_local
day_local	2-digit day of month (local) when the trip occurred.	dd (01 to 31)	day_local
year	4-digit year (local) when the trip occurred.	YYYY	year
time_start	The time (local) at which the fishing vessel left the dock to tend the net.	HHMM	time_start
bycatch_reduct_gear	Indicates whether the trip used a bycatch reduction gear, or whether the trip was a control trial. If the trip was a gear manipulation trial, the value will indicate which bycatch reduction gear was used. If the trip was a control trial, the value will be 'CONTROL'.	text	no_bcodmo_term
trial_id	Indicates which gear type the trip was testing (includes both gear manipulation and control trials). Trial type (gear manipulation or control) can be determined by looking at the 'bycatch_reduct_gear' parameter.	text	instrument
weight_lbs	If the fisherman gave a verbal estimation of the total catch in pounds, the value is given here. If the total catch was not estimated in pounds, this field contains 'nd'.	pounds	weight
take	If the total catch was recorded as number of totes, trays, or dip nets, the number of totes, trays, or dip nets taken is recorded here. If there was no take, but simply a biosample taken, 'nd' or '0' is given.	varies	num_caught
take_unit	The unit of take; either TOTE, TRAY, or DIP_NET.	text	no_bcodmo_term
sample_type	The type of sample; either BIOSAMPLE or TAKE. BIOSAMPLE = the sample was taken specifically to test gear effectiveness, and the fisherman did not plan on retaining the catch otherwise. TAKE = the sample was taken from the portion of the fisherman's catch that would be sold for market value.	text	sample_descrip
effort	The unique effort identifier within a specific trip. Multiple effort_id numbers under the same trip number indicate that more than one sample type was taken from the same haul. This was done when the fisherman's take was different than the total catch (i.e. when the entire catch would not have been kept, or even brought on board, if not part of the sampling effort.)	unitless	no_bcodmo_term
sample_amt	The quantity of the sample in totes, trays, or dip nets.	varies	numb_obs
sample_amt_unit	The type of sample quantity; either TOTE, TRAY, or DIP_NET.	text	no_bcodmo_term
catch_id	The unique identifier number regarding the species in the specific effort. Each species caught within a single effort will have a unique identifier number.	unitless	sample
count	The total number of individuals of a specific species within an effort.	unitless	count
common_name	The common name of the species sampled.	text	common_name
species	The scientific name of the species sampled.	text	species
sample	The unique identifier for the length sample of a given species' within a specific catch.	unitless	sample
fish_len	The length of the sample in millimeters. All values are total length.	millimeters	fish_len
freq_fish_len	The frequency of the sample length. The value will be 1 unless the sample represents a count of individuals that were not measured. In this case, freq_fish_len is the number of individuals of a specific species that were counted but not measured.	unitless	no_bcodmo_term
comments	Comments recorded by the observer regarding catch, fishing practices, fishermen's comments, gear effectiveness, and the proportion of total catch was sampled.	text	comment
lat_start	Latitude of the starting location of the trip. Positive values = North.	decimal degrees	lat_start
lon_start	Longitude of the starting location of the trip. Negative values = West.	decimal degrees	lon_start

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Dataset: juv_fish_bycatch_redux