Dataset: Larval fish abundance from Bongo plankton net tows

Name: Abundances of larval Northern Anchovy (Engraulis mordax), Rockfish (Sebastes spp., and other/unidentified larvae from Bongo plankton net tows conducted in the subtropical Southern California Bight from January to April 2021
Published: 2023-05-02
Keywords: oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.895121.1

Spatial Extent: N:34.45 E:-117.279 S:32.8468 W:-120.8

Temporal Extent: 2021-01-23 - 2021-04-15

Project:

RAPID: Understanding the unprecedented anchovy response to warm-water conditions in the California Current (RAPID Anchovy Response)

Principal Investigator:

Brice X. Semmens (University of California-San Diego Scripps, UCSD-SIO)

Co-Principal Investigator:

Michael R. Landry (University of California-San Diego Scripps, UCSD-SIO)

Scientist:

Rasmus Swalethorp (University of California-San Diego Scripps, UCSD-SIO)

Contact:

Rasmus Swalethorp (University of California-San Diego Scripps, UCSD-SIO)

BCO-DMO Data Manager:

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

Version:

Version Date:

2023-05-02

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Abundances of larval Northern Anchovy (Engraulis mordax), Rockfish (Sebastes spp., and other/unidentified larvae from Bongo plankton net tows conducted in the subtropical Southern California Bight from January to April 2021

Abstract:

This dataset includes abundances of larval Northern Anchovy (Engraulis mordax), Rockfish (Sebastes spp., and other/unidentified larvae from Bongo plankton net tows conducted in the subtropical Southern California Bight from January to April 2021. Net tows were carried out on several cruises aboard R/V Bob and Betty Beyster and R/V Shearwater.

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Archival Copy

Version Date	Archive	Persistent Identifier (PID)	Date PID Issued
2023-05-02	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.895121.1	2023-05-02

Methods & Sampling

This study was carried out within the temperate to subtropical Southern California Bight and surrounding coastal areas between 32° and 35° North, and 117° and 120° West. Specific locations sampled fall within the CalCOFI and CCE-LTER programs' quarterly survey grid from lines 76.7 to 93.4 and stations 26 to 55.

Sampling took place from January to April 2021 on R/V Bob and Betty Beyster cruises BBB2101, BBB2102, and BBB2104 and on R/V Shearwater cruise SW2104. Each cruise number is composed of one or more day trips using one of the two research vessels. The two-three letters indicate the research vessel, and the four digits indicate YYMM.

Larval fish were collected using a 71-centimeter (cm diameter dual Bongo plankton net system equipped with a small CTD to record depth and physical variables during horizontal net tows at a ship speed of 1.5 to 2.5 knots down to 14 to 36 meters (m) depth, depending on bottom depth. The Bongo was equipped with two 505-micrometer (µm) mesh-size nets and a flowmeter mounted in the center of one of them.

Once the net was retrieved the cod-ends were immediately placed in a saltwater ice bath and the nets were gently rinsed with saltwater. The content of the cod-ends was then concentrated onto a 200-300 µm mesh-size sieve, transferred into glass jars, and preserved in Tris-buffered 95% ethanol as quickly as possible. After a few days of storage, the alcohol was exchanged. The samples were sorted under a dissecting microscope and fish larvae were identified based on body shape and pigmentation patterns.

Known Problems/Issues:
The Rockfish data contain some gaps for samples where they were not identified and counted. In those cases, any Rockfish present will be included in the Other / Unidentified category.

Data Processing Description

Data Processing:
CastAway-CTD software version 1.3 (firmware version v026_r2818) was used for data acquisition and processing using default correction algorithms and binned over 0.3 decibar changes. For more information on data processing, please see the manual at https://www.sontek.com/castaway-ctd.

The flowmeter was calibrated between cruises to accurately calculate the volume of water strained by the net and the abundance of fish larvae. It was assumed the volume would be the same for both the starboard and port side net.

BCO-DMO Processing:
- converted date-time fields to ISO 8601 format;
- renamed fields to comply with BCO-DMO naming conventions;
- corrected typo in dataset: changed "Andhovy" to "Anchovy" in the Common_name column.

Data Files

File
larval_fish_abundance_from_bongo_plankton_tows.csv (Comma Separated Values (.csv), 25.84 KB) MD5:6515892a9cf8bdcbc102409b88ed7387 Primary data file for dataset ID 895121.

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-2053719

Deployments

Deployment	Start Date	Platform	Investigator
BBB2101	2021-01-23	R/V Bob and Betty Beyster	Rasmus Swalethorp (Chief Scientist)	data info
BBB2102	2021-02-01	R/V Bob and Betty Beyster	Rasmus Swalethorp (Chief Scientist)	data info
BBB2104	2021-04-06	R/V Bob and Betty Beyster	Rasmus Swalethorp (Chief Scientist)	data info
SW2104	2021-04-13	R/V Shearwater	Rasmus Swalethorp (Chief Scientist)	data info

Instruments

Bongo Net

Supplied Name: 71 cm diameter dual Bongo plankton net system

Supplied Description:

Instrument Type

Generic Name: Bongo Net

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/NETT0009/

Generic Description:

A Bongo Net consists of paired plankton nets, typically with a 60 cm diameter mouth opening and varying mesh sizes, 10 to 1000 micron. The Bongo Frame was designed by the National Marine Fisheries Service for use in the MARMAP program. It consists of two cylindrical collars connected with a yoke so that replicate samples are collected at the same time. Variations in models are designed for either vertical hauls (OI-2500 = NMFS Pairovet-Style, MARMAP Bongo, CalVET) or both oblique and vertical hauls (Aquatic Research). The OI-1200 has an opening and closing mechanism that allows discrete "known-depth" sampling. This model is large enough to filter water at the rate of 47.5 m3/minute when towing at a speed of two knots. More information: Ocean Instruments, Aquatic Research, Sea-Gear

Flow Meter

Supplied Name: General Oceanic Inc. Flowmeter

Supplied Description:

Instrument Type

Generic Name: Flow Meter

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/388/

Generic Description:

General term for a sensor that quantifies the rate at which fluids (e.g. water or air) pass through sensor packages, instruments, or sampling devices. A flow meter may be mechanical, optical, electromagnetic, etc.

SonTek CastAway-CTD

Supplied Name: SonTek CastAway CTD model CC1403002

Supplied Description:

Instrument Type

Generic Name: SonTek CastAway-CTD

Acronym: CastAway-CTD

Generic Description:

The Sontek CastAway-CTD (manufactured by Xylem) is a handheld castable instrument that provides instantaneous profiles of temperature, salinity, and sound speed. Each cast is referenced with both time and location using its built-in GPS receiver. The CastAway software displays profiles of the casts in addition to mapping the locations of the data collection points. The CastAway-CTD has a 5 Hz response and sampling rate, accurate to 0.1 (PSS-78), 0.05° Celsius.

Conductivity range is 0 to 100,000 µS/cm.
Temperature range is -5° to 45° Celsius.
Pressure range is 0 to 100 decibars.

Further specs and information can be found on the manufacturer's website: https://www.xylem.com/en-us/brands/wtw/wtw-products/castaway-ctd/

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
Cruise	Cruise identifier	unitless	cruise_id
ISO_DateTime_UTC	Date and time (UTC) in ISO 8601 format Format: %Y-%m-%dT%H:%MZ	unitless	ISO_DateTime_UTC
ISO_DateTime_PDT	Date and time (PDT) in ISO 8601 format Format: %Y-%m-%dT%H:%M	unitless	ISO_DateTime_Local
Line	CalCOFI line	unitless	site
St	CalCOFI station	unitless	station
Lat	Latitude	decimal degrees North	lat
Long	Longitude	decimal degrees East	lon
Tow_depth	Maximum depth of net	meters (m)	depth_max
Net	Indicates starboard (STB) or port (PORT) net	unitless	net
Taxa	Latin name of larval fish	unitless	taxon
Common_name	Common name of larval fish	unitless	common_name
Count	Number of larvae caught in net	number of individuals	count
ind_per_cubic_m	Larval abundance per cubic meter	individuals per cubic meter	abundance
ind_per_ten_sq_m	Larval abundance per 10 square meters	individuals per ten square meters	abundance

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Database

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Dataset: Larval fish abundance from Bongo plankton net tows