FishSOOP-notes

OceanCurrent - FishSOOP - notes

Introduction to IMOS FishSOOP

FishSOOP (Fishing Vessel as Ships of Opportunity Program) turns everyday fishing activity into ocean science fieldwork. By attaching small sensors to commercial fishing gear or equipment operated by citizen scientists, FishSOOP collects measurements of sea temperature and depth in coastal waters on and off the continental shelf.

All data are quality-controlled and made available open source through the Australian Ocean Data Network (AODN) in near real time. This provides unique insights into ocean conditions where it matters most to the fishing industry (where fishing occurs). FishSOOP bridges the gap between fisheries and science: supporting sustainable ocean use, improving climate and ecosystem understanding, and empowering communities with open data.

Understanding the plots

data finder data visualiser

The FishSOOP dataset comprises a large number of closely spaced deployments of temperature sensors, unevenly distributed but mostly over the continental shelf. The program started in 2021. To help you explore this dataset, we divide the data into daily, regional windows. To find data for your region(s) of interest, go to the data finder and navigate time (using the arrows or the calendar reached by clicking the year) until your region shows up as having data, which will be indicated by the regional boundary line being thick, and a count of the number of deployments that day being shown. If the boundary is a thin line it means there were deployments at some point in the year, so clicking takes you to a calendar. A dashed bounding box means no deployments that year.
These data finder pages also give a first glimpse of all the FishSOOP temperature data for the day, by showing the temperature anomaly observed by each deployment, averaged over 24h within depths of 0-50m.
To explore the temperature data within a region using the data visualiser pages, click anywhere within the relevant box.

The data visualiser pages have five panels, all of which show the FishSOOP temperature data from all deployments within a region during a 24h period. The downside of this approach is that sometimes there is too much data for one plot. But we think that more often, this is outweighed by the value of comparing the observed data with neighbouring values.
Left panel: The FishSOOP temperature observations from all deployments that day are shown as black lines. To get a sense of how 'normal' these observations are, we include the climatological average profile (as a bold blue line) at the location of the deepest FishSOOP deployment, as well as the average plus 1, 2 and 3 standard deviations (as thin blue, green and red lines - see key). The climatology used is the CSIRO Atlas of Regional Seas (CARS 2009).
Centre panels, top, overlays the locations of FishSOOP data on a Sea Surface Temperature image. The colourbar for both SST and the FishSOOP 0-50m average temperature spans the CARS surface temperature range across the domain shown, plus [-2 2] °C (see two lines on the colour bar denoting the CARS range without buffer). Hover on the circled FishSOOP data to see the sensor serial number, maximum depth reached and the water depth according to GEBCO_2019.
Centre panels, bottom, shows colour-coded FishSOOP temperature observations vs time and depth. FishSOOP temperature sensors are attached to a wide variety of fishing gear, some of which go to the sea floor for several days, while others go to mid-depth for a while. The FishSOOP data does not include the total water depth so we add the GEBCO_2019 estimate of this as a horizontal dashed line spanning the duration of the deployment. If this depth is beyond the axis limits it is written at the bottom of the plot.
Right panels, top and bottom, show the averages, within depth ranges defined by the top and bottom halves of the deepest deployment, of the anomaly of the FishSOOP observed temperature. These anomalies are with reference to the CARS temperature estimates at the individual deployment locations - not a single location for all (as used in the left panel).

data finder	data visualiser

The FishSOOP dataset comprises a large number of closely spaced deployments of temperature sensors, unevenly distributed but mostly over the continental shelf. The program started in 2021. To help you explore this dataset, we divide the data into daily, regional windows. To find data for your region(s) of interest, go to the data finder and navigate time (using the arrows or the calendar reached by clicking the year) until your region shows up as having data, which will be indicated by the regional boundary line being thick, and a count of the number of deployments that day being shown. If the boundary is a thin line it means there were deployments at some point in the year, so clicking takes you to a calendar. A dashed bounding box means no deployments that year. These data finder pages also give a first glimpse of all the FishSOOP temperature data for the day, by showing the temperature anomaly observed by each deployment, averaged over 24h within depths of 0-50m. To explore the temperature data within a region using the data visualiser pages, click anywhere within the relevant box.	The data visualiser pages have five panels, all of which show the FishSOOP temperature data from all deployments within a region during a 24h period. The downside of this approach is that sometimes there is too much data for one plot. But we think that more often, this is outweighed by the value of comparing the observed data with neighbouring values. Left panel: The FishSOOP temperature observations from all deployments that day are shown as black lines. To get a sense of how 'normal' these observations are, we include the climatological average profile (as a bold blue line) at the location of the deepest FishSOOP deployment, as well as the average plus 1, 2 and 3 standard deviations (as thin blue, green and red lines - see key). The climatology used is the CSIRO Atlas of Regional Seas (CARS 2009). Centre panels, top, overlays the locations of FishSOOP data on a Sea Surface Temperature image. The colourbar for both SST and the FishSOOP 0-50m average temperature spans the CARS surface temperature range across the domain shown, plus [-2 2] °C (see two lines on the colour bar denoting the CARS range without buffer). Hover on the circled FishSOOP data to see the sensor serial number, maximum depth reached and the water depth according to GEBCO_2019. Centre panels, bottom, shows colour-coded FishSOOP temperature observations vs time and depth. FishSOOP temperature sensors are attached to a wide variety of fishing gear, some of which go to the sea floor for several days, while others go to mid-depth for a while. The FishSOOP data does not include the total water depth so we add the GEBCO_2019 estimate of this as a horizontal dashed line spanning the duration of the deployment. If this depth is beyond the axis limits it is written at the bottom of the plot. Right panels, top and bottom, show the averages, within depth ranges defined by the top and bottom halves of the deepest deployment, of the anomaly of the FishSOOP observed temperature. These anomalies are with reference to the CARS temperature estimates at the individual deployment locations - not a single location for all (as used in the left panel).

Use cases

Cold-core eddy off Byron Bay
Cold core eddies are not always very cold at the surface. Oceanographers are more likely to infer their presence from seeing water circulating in a clockwise direction in an SST image (see top middle panel), or a depression of the sea level in satellite-based observations. The FishSOOP subsurface (60-120m) temperature anomalies in the centre of this eddy off northern NSW are about -2 °C (see bottom right panel), signaling an uplift of the isotherms by about 40m (see slope of blue line in left panel). The deep temperature minimum of 18.5 ° is about 1.5 standard deviations colder than the climatological mean, suggesting that this is a moderately strong eddy.

Bass Strait Winter Cascade or Tasman Sea water?
In July 2024, sensor 785 was deployed several times to about 430m at the upper continental slope off eastern Bass Strait. It was retrieved each time within about 7h. The deployment and retrieval temperature profiles were mostly similar but on both 20 July and 30 July, a difference of about 4 ° between the downward and upward measurements was recorded between 330m and 430m. What could have caused such big changes? One potential explanation is that the retrieval encountered some Bass Strait Winter Cascade water, but the deployment did not. Indeed, the SST images show that the surface water in Bass Strait was much colder (about 13 °) than the water off the shelf, so some of this cold (and therefore dense) water might have been falling off the shelf like an underwater waterfall. But why the change over just a few hours? The sensor depth was constant (see left and centre bottom panels), suggesting it was stationary on the bottom, and therefore that the path taken by, or the strength of, the Cascade was varying with time, perhaps due to the tide. Alternatively, maybe the cold water came from below rather than from above. The cold water sampled by sensor 785 was just 9 °C, somewhat colder than we expect to find in Bass Strait water. See this July 2021 glider mission, for example which found the water to be about 12.5 °C at all depths in the central basin. Where do we expect to find 9 ° water? An Argo profile on 12 July 2024 found it at about 500m in deep water east of Flinders Island, suggesting that what sensor 785 found was Tasman Sea water, temporarily upwelled at the continental slope, perhaps by an internal tide. Regardless of the cause, it is worth noting that this was such a large-amplitude event that some of the data (the warmest at depth) would have been flagged as bad if values outside 3 standard deviations from climatology were rejected.

Swarm deployment of five sensors
It is not that often that oceanographers deploy five sensors over 3h and 20km. But that's what this fisher did in deep water off Stockton Bight on 4 March 2024. The SST image suggests that these deployments were into the warm waters of the East Australian Current. But the sensors tell a different story. The surface waters were indeed warm (26 °C, 1 standard deviation above climatology) but this was just a very thin layer, just 10 to 20m thick. Beneath that warm water was water about 4 ° colder, which was what a sensor at the coast was finding from surface to 35m. This is not really surprising, but is interesting to see so clearly.

Internal tides on the North West Shelf
Sensor 445 was busy on 31 Dec 2024 documenting some large-amplitude internal tides north of Dampier on the North West Shelf. Six deploments to 70 to 100m were made over 24h, spanning a distance of about 20km. All recorded a surface temperature close to 31 °C and a bottom temperature of 27.5 °C. Where they differed was in the depth of the 29 ° isotherm, which varied from about 75m to 30m. The intervals between maxima and between minima are both about 12h, confirming that these are internal tides, which is what this region is known for in summer when shelf waters are stratified.

South Australian algal bloom
South Australia suffered a major Harmful Algal Bloom (HAB)that is thought to be due, at least in part, to a marine heatwave (MHW) that started around September 2024. Sensor 786 was deployed many times during the MHW, but mostly near the shelf edge off the Bonney Coast, between Portland and Robe, where it monitored the temperature of the South Australian Current. The 10 September 2024 deployment of sensor 786 found that water temperatures of the SAC were 2 to 5 degrees warmer than climatology, and below 300m, well in excess of climatology plus 3 standard deviations. It is hard to believe that this strong flow of warm water did not set the stage somehow (perhaps by suppressing the usual summer upwelling) for the waters near the Fleurieu Peninsula to become very hot in March 2025 when the HAB began. These observations by sensors 786 (and 421, which sampled inshore) are sure to be of value as oceanographers continue to learn more about the causes of this extreme event.

The South Australian Current off Tasmania
Much of the South Australian Current continues beyond the border with Victoria along the shelf edge west of Bass Strait then along the Tasmanian shelf edge where it is sometimes referred to as the Zeehan Current. Did the strong SAC observed by sensor 786 off the Bonney Coast (described above) show up off Tasmania as a strong Zeehan Current? Yes, according to sensor 785's measurements on 10 September 2024 at the shelf edge off Macquarie Harbour, which found near-normal temperature at the surface, but an anomaly of +3 ° at 400m, well outside of climatology plus 3 standard deviations. Notably, the temperature is completely isothermal from 0 to 400m.

Cold water near bottom at 90m off Tiwi Island
From 20 May to 2 July 2024, several FishSOOP sensors recorded the presence of a very cold layer of water in the bottom 10m over the outer continental shelf. This water was up to 7 °C colder (just outside 3 standard deviations) than the overlying water which was 29 °C (slightly warmer than climatology). The location of these observations was in 90m of water, NNE of Tiwi Island, not far from where IMOS has maintained a current meter mooring (NWSLYN, in 195m of water) since 2019. In June 2024, when FishSOOP recorded the cold layer, NWSLYN recorded temperatures of 16 ° to 18 ° at 154m as well as tidal period current velocities of about 0.2m/s in antiphase above and below 100m. These very different observing systems are therefore consistent and the picture that emerges is that internal tides are energetic at the NWSLYN site in June 2024 because the site is deep enough that the thermocline is near mid-depth. The FishSOOP observations, however, are in shallower water. Is the cold layer running up the slope like a wave coming onto a beach? Another question remaining is "why are the deep temperatures so much (about 10 °C) colder than those recorded by the ITFMHB mooring in a similar depth 250km to the WSW?"

FishSOOP program data processing

Technical details of the FishSOOP program are documented by Lago, V., M. Roughan and S. Caon. (2025) IMOS Fishing Vessels as Ships of Opportunity (FishSOOP), Real-time Quality Assurance and Quality Control Practice Manual, Version 1.0. Integrated Marine Observing System. doi.org/10.26198/sp0r-p448.

OceanCurrent does not perform any additional editing of the data set that is available to all at the IMOS data server. We show all data that are flagged as good (flag value 1) in the FV001. Data flagged otherwise (including 2='potentially correctable') are not shown (they are not many).

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Revision history

20 October 2025: First exposure draft for SC approval. (Accessable only to those who have been given a URL by email)

To Do

revise/edit descriptive material above VL - done
present exposure draft to SC for comment MR- done
broaden domain to encompass NZ, S Pac (110-200E,55S-5N) DG
make edits depending on SC feedback on exposure draft DG
modernise website appearance and navigation (to match the rest of Ocean Current) RS+DG
activate and monitor daily updating of data cache and website images and navigation DG
in existing OceanCurrent pages, e.g. 4h SST: include locations of FishSOOP data, with links to profile visualiser pages GSP+DG
make links in OceanCurrent front page and menus to the FishSOOP subsection, and publish a news item announcing it (with some interesting usage examples) DG+MR
IMOS website and socials announcement MW
add more visualisations of FishSOOP data, e.g. monthly-averaged and 2023-25-average temperature anomaly DG, suggestions from all and SC

[Conditions of use]

Cold-core eddy off Byron Bay Cold core eddies are not always very cold at the surface. Oceanographers are more likely to infer their presence from seeing water circulating in a clockwise direction in an SST image (see top middle panel), or a depression of the sea level in satellite-based observations. The FishSOOP subsurface (60-120m) temperature anomalies in the centre of this eddy off northern NSW are about -2 °C (see bottom right panel), signaling an uplift of the isotherms by about 40m (see slope of blue line in left panel). The deep temperature minimum of 18.5 ° is about 1.5 standard deviations colder than the climatological mean, suggesting that this is a moderately strong eddy.
Bass Strait Winter Cascade or Tasman Sea water? In July 2024, sensor 785 was deployed several times to about 430m at the upper continental slope off eastern Bass Strait. It was retrieved each time within about 7h. The deployment and retrieval temperature profiles were mostly similar but on both 20 July and 30 July, a difference of about 4 ° between the downward and upward measurements was recorded between 330m and 430m. What could have caused such big changes? One potential explanation is that the retrieval encountered some Bass Strait Winter Cascade water, but the deployment did not. Indeed, the SST images show that the surface water in Bass Strait was much colder (about 13 °) than the water off the shelf, so some of this cold (and therefore dense) water might have been falling off the shelf like an underwater waterfall. But why the change over just a few hours? The sensor depth was constant (see left and centre bottom panels), suggesting it was stationary on the bottom, and therefore that the path taken by, or the strength of, the Cascade was varying with time, perhaps due to the tide. Alternatively, maybe the cold water came from below rather than from above. The cold water sampled by sensor 785 was just 9 °C, somewhat colder than we expect to find in Bass Strait water. See this July 2021 glider mission, for example which found the water to be about 12.5 °C at all depths in the central basin. Where do we expect to find 9 ° water? An Argo profile on 12 July 2024 found it at about 500m in deep water east of Flinders Island, suggesting that what sensor 785 found was Tasman Sea water, temporarily upwelled at the continental slope, perhaps by an internal tide. Regardless of the cause, it is worth noting that this was such a large-amplitude event that some of the data (the warmest at depth) would have been flagged as bad if values outside 3 standard deviations from climatology were rejected.
Swarm deployment of five sensors It is not that often that oceanographers deploy five sensors over 3h and 20km. But that's what this fisher did in deep water off Stockton Bight on 4 March 2024. The SST image suggests that these deployments were into the warm waters of the East Australian Current. But the sensors tell a different story. The surface waters were indeed warm (26 °C, 1 standard deviation above climatology) but this was just a very thin layer, just 10 to 20m thick. Beneath that warm water was water about 4 ° colder, which was what a sensor at the coast was finding from surface to 35m. This is not really surprising, but is interesting to see so clearly.
Internal tides on the North West Shelf Sensor 445 was busy on 31 Dec 2024 documenting some large-amplitude internal tides north of Dampier on the North West Shelf. Six deploments to 70 to 100m were made over 24h, spanning a distance of about 20km. All recorded a surface temperature close to 31 °C and a bottom temperature of 27.5 °C. Where they differed was in the depth of the 29 ° isotherm, which varied from about 75m to 30m. The intervals between maxima and between minima are both about 12h, confirming that these are internal tides, which is what this region is known for in summer when shelf waters are stratified.
South Australian algal bloom South Australia suffered a major Harmful Algal Bloom (HAB)that is thought to be due, at least in part, to a marine heatwave (MHW) that started around September 2024. Sensor 786 was deployed many times during the MHW, but mostly near the shelf edge off the Bonney Coast, between Portland and Robe, where it monitored the temperature of the South Australian Current. The 10 September 2024 deployment of sensor 786 found that water temperatures of the SAC were 2 to 5 degrees warmer than climatology, and below 300m, well in excess of climatology plus 3 standard deviations. It is hard to believe that this strong flow of warm water did not set the stage somehow (perhaps by suppressing the usual summer upwelling) for the waters near the Fleurieu Peninsula to become very hot in March 2025 when the HAB began. These observations by sensors 786 (and 421, which sampled inshore) are sure to be of value as oceanographers continue to learn more about the causes of this extreme event.
The South Australian Current off Tasmania Much of the South Australian Current continues beyond the border with Victoria along the shelf edge west of Bass Strait then along the Tasmanian shelf edge where it is sometimes referred to as the Zeehan Current. Did the strong SAC observed by sensor 786 off the Bonney Coast (described above) show up off Tasmania as a strong Zeehan Current? Yes, according to sensor 785's measurements on 10 September 2024 at the shelf edge off Macquarie Harbour, which found near-normal temperature at the surface, but an anomaly of +3 ° at 400m, well outside of climatology plus 3 standard deviations. Notably, the temperature is completely isothermal from 0 to 400m.
Cold water near bottom at 90m off Tiwi Island From 20 May to 2 July 2024, several FishSOOP sensors recorded the presence of a very cold layer of water in the bottom 10m over the outer continental shelf. This water was up to 7 °C colder (just outside 3 standard deviations) than the overlying water which was 29 °C (slightly warmer than climatology). The location of these observations was in 90m of water, NNE of Tiwi Island, not far from where IMOS has maintained a current meter mooring (NWSLYN, in 195m of water) since 2019. In June 2024, when FishSOOP recorded the cold layer, NWSLYN recorded temperatures of 16 ° to 18 ° at 154m as well as tidal period current velocities of about 0.2m/s in antiphase above and below 100m. These very different observing systems are therefore consistent and the picture that emerges is that internal tides are energetic at the NWSLYN site in June 2024 because the site is deep enough that the thermocline is near mid-depth. The FishSOOP observations, however, are in shallower water. Is the cold layer running up the slope like a wave coming onto a beach? Another question remaining is "why are the deep temperatures so much (about 10 °C) colder than those recorded by the ITFMHB mooring in a similar depth 250km to the WSW?"