CPUE Estimation and Standardization Based on VMS: A Case Study for Squid-Jigging Fishery in the Equatorial of Eastern Pacific Ocean
Round 1
Reviewer 1 Report
This well written paper presents an analysis of the squid fisheries within a particular region based on a variety of data sources. The authors do a good job in bringing the data together and highlighting the general trends with special emphasis on the use of VMS. My comments are minor.
1. line 63 this sentence needs linking to the one before.
2. line 146 clumsy sentence here. Plus is there is scope for the fishers to switch the VMS off?
3. line 196 change 'has' to have
4. line 195 is there use in combining both direction and speed (vector) here? this might suit prevailing winds and currents?
5. line 168 please detail the SST more. Is it daily maximum etc? is there scope to use more sophisticated indices like degree heating weeks commonly used in corals?
6. line 108 can you present a summary of the catch data? like a histogram or such like.
Author Response
Point 1: line 63 this sentence needs linking to the one before.
Response 1: Thanks to the reviewer's comments. To link the preceding and following sentences, we have revised this sentence in line 63 to “The generalized linear model (GLM) and generalized additive model (GAM) have been extensively used to standardize CPUE. GLM is designed for linear relationships, but the relationship between the variables affecting CPUE was found to be complex and may be non-linear in some studies, so it does not apply well in many situations”.
Point 2: line 146 clumsy sentence here. Plus is there is scope for the fishers to switch the VMS off?
Response 2: Thanks to the reviewer's comments, we have modified the sentence in line 146. With regard to VMS, there is no scope or motivation for the Chinese squid jigging vessels to switch the VMS based on the domatis laws, rules as well as management meatuses of SRPRFMO (CMM 06 2020 Establishment of the Vessel Monitoring System in the SPRFMO Convention Area). By the way, considering the loss of satellite signal and ensure the frequency of VMS data reporting, the squid vessels are equipped with 2 or 3 VMS devices at the same time such as IPS, Argos, OCEANNA, FLCOM et.al.
Point 3: line 196 change 'has' to have.
Response 3: Thanks to the reviewer's comments, we have changed ‘has’ to ‘have’ in line 196.
Point 4: line 195 is there use in combining both direction and speed (vector) here? this might suit prevailing winds and currents?
Response 4: Thanks to the reviewer's comments. We only used speed to identify the status of fishing vessels, and we will remove the content about heading. We fully agree with the reviewer on prevailing winds and currents. The trajectory of squid jigging vessels should be the result of the combined effect of prevailing winds, currents and vessels (anchors, sails), so that on the same night, the theoretical trajectory of a vessel in operation and other vessels in operation in the vicinity should be parallel, which can be used to test whether our identification of the status of the fishing vessels is correct, or to improve the accuracy of the determination of the status of the fishing vessels. In this sense, it is not necessary to use prevailing wind and current data directly when identifying the status of fishing vessels, but rather to consider the trajectory. The next step will be to refine the method of identifying the status of fishing vessels based on the reviewers' comments.
Point 5: line 168 please detail the SST more. Is it daily maximum etc? is there scope to use more sophisticated indices like degree heating weeks commonly used in corals?
Response 5: SST used in this article is the monthly mean values with 0.25-degree spatial resolution that obtain from the EU’s Copernicus. Monthly SST data and other environmental data were matched the catch data based on time and location with the same resolution. Thanks to the reviewer’s question or suggestion that give us a new view to explore the relationships between jumbo flying squid and marine environment. DHW is a new and very interesting indices for us, we will try to use it as well as weekly 5 km SST for CPUE standardization in the future.
Point 6: line 108 can you present a summary of the catch data? like a histogram or such like.
Response 6: We completely agree with the reviewers on that. We have added a histogram about catch data in the paper.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Interesting MS and well prepared. However, it must be corrected before publication. I included my detailed remarks and comments in the text. To see them all, open the file in Acrobat Reader. Particular attention should be paid to the titles Tables and Figures. They should be much more informative.
Comments for author File: 
Comments.pdf
Author Response
Point 1: line 23 this sentence uses passive form if possible.
Response 1: Thanks to the reviewer's comments. We have revised the sentence in line 23 to " Then, the generalized linear model (GLM) and generalized additive model (GAM) were applied to conduct CPUE standardization considering spatio-temporal factors and environmental variables including sea surface temperature (SST), sea surface salinity (SSS), sea surface height (SSH) and chlorophyll-a (Chl_a). ".
Point 2: line 30 this sentence uses passive form if possible.
Response 2: Thanks to the reviewer's comments. We have revised the sentence in line 30 to " In addition, the nominal and standardized CPUEs were compared based on fishing hours and fishing days. ".
Point 3: line 53 please specific the factors which can influence CPUE.
Response 3: Thanks to the reviewer's comments. We have specified this as required.
Point 4: line 74 modify the location of the citation marker.
Response 4: Thanks to the reviewer's comments. We have made changed as required.
Point 5: line 100 this sentence uses passive form if possible.
Response 5: Thanks to the reviewer's comments. We have revised the sentence in line 100 to " the VMS data was used to estimate the total number of fishing hours. ".
Point 6: line 103 this sentence uses passive form if possible.
Response 6: Thanks to the reviewer's comments. We have revised the sentence in line 103 to " And then, the nominal CPUE was calculated and GLM and GAM were applied to conduct CPUE standardization. ".
Point 7: line 133 this sentence uses passive form if possible.
Response 7: Thanks to the reviewer's comments. We have revised the sentence in line 133 to " In this paper, the squid jigging vessel state identification method adopted by Yang et al was referred. ".
Point 8: line 138 modify the location of the citation marker.
Response 8: Thanks to the reviewer's comments, we have made changed as required.
Point 9: line 206 the figure’s title must be more informative.
Response 9: Thanks to the reviewer's comments. We have revised the the figure's title to " Histogram of speed frequency distribution ".
Point 10: line 213 the figure’s title must be more informative.
Response 10: Thanks to the reviewer's comments. We have revised the the figure's title to " Statistical distribution tests for ln(CPUEh+1): (a) frequency distribution of ln(CPUEh+1); (b) nominal Q-Q plot of ln(CPUEh+1). ".
Point 11: line 220 line feed at marker.
Response 11: Thanks to the reviewer's comments, we have made a line feed at marker.
Point 12: line 221 the table’s title must be more informative.
Response 12: Thanks to the reviewer's comments. We have revised the table's title to " The significance test of explained variables in Generalized linear models (GLM) ".
Point 13: line 228 the table’s title must be more informative.
Response 13: Thanks to the reviewer's comments. We have revised the the table's title to " Summary analysis of deviance for Generalized additive models (GAM) ".
Point 14: modification of the horizontal coordinates in Figure 3.
Response 14: Thanks to the reviewer's comments, we have modified the horizontal coordinates in Figure 3.
Point 15: line 245 the figure’s title must be more informative.
Response 15: Thanks to the reviewer's comments. We have revised the the figure's title to " Relationship between monthly nominal CPUE and GAM standardized CPUE of the Chinese squid jigging fishery in the equatorial waters of Eastern Pacific.".
Point 16: line 249 the figure’s title must be more informative.
Response 16: Thanks to the reviewer's comments. We have revised the figure's title to " The relationship of mean monthly CPUE between two units: (a) nominal CPUE; (b) GAM standardized CPUE.".
Point 17: line 258 delete enter at marker.
Response 17: Thanks to the reviewer's comments, we have deleted enter at marker.
Point 18: line 276 add English and full Latin name.
Response 18: Thanks to the reviewer's comments, we have added English and full Latin name.
Point 19: line 287 modify the location of the citation marker.
Response 19: Thanks to the reviewer's comments, we have made changed as required.
Point 20: line 322 Italics.
Response 20: Thanks to the reviewer's comments, we have made changed as required.
Point 21: line 344 modify the location of the citation marker.
Response 21: Thanks to the reviewer's comments, we have made changed as required.
Point 22: line 356 the figure’s title must be more informative.
Response 22: Thanks to the reviewer's comments. We have revised the the figure's title to " Monthly distribution of GAM standardized CPUE and predicted CPUE for squid jigging fishery in the equatorial waters of Eastern Pacific.".
Point 23: line 362 change 'it is' to 'it was'.
Response 23: Thanks to the reviewer's comments, we have changed 'it is' to 'it was' in line 362.
Author Response File: Author Response.docx
